Compounding Disasters in Gulf Coast Communities 2020-2021: Impacts, Findings, and Lessons Learned (2024)

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1 Introduction Experiencing a disaster—a hurricane, tornado, flood, severe winter storm, or global pandemic—wreaks havoc on the lives and livelihoods of individuals, families, communities, 1 and entire regions. For people who live in the five U.S. states outlining the coastline of the Gulf of Mexico (GOM) region—Texas, Louisiana, Mississippi, Alabama, and Florida—living through and trying to recover from such a disaster is not a once-in-a-lifetime experience but an enduring reality. Between 2020 and 2021, seven major hurricanes and a severe winter storm (later named Uri) severely affected communities across the GOM region, with each of these events ultimately being designated a billion-dollar disaster. 2 These storms, some arriving in the same region within weeks of one another, occurred while communities were coping with the illness, death, uncertainty, and disruption brought about by the COVID-19 pandemic. This constellation of sequential, sudden-onset disasters imposed compounding stress on a region with multifaceted and persistent socioeconomic and socioenvironmental disparities. As a result of these disparities, communities with heightened vulnerability and exposure to hazards experienced disproportionate impacts from disaster events. To these communities, the moniker billion-dollar disaster fails to encapsulate a broader scope of physical, economic, social, cultural, and emotional damages caused by unrelenting disasters. These communities are on the frontlines 3 of climate change, 1 Community, as it is defined in this report, predominantly refers to “members of a collectivity, who share a common territorial area as their base of operation for daily activities.” In some instances, it refers to a social group whose members are bound together by the sense of belonging created out of everyday contacts covering the entire range of human activities ((Parsons, 1969, as cited in NASEM, 2021). 2 The term “billion-dollar disaster” refers to weather and climate events for which the overall economic damages/costs reached or exceeded $1 billion (including Consumer Price Index [CPI] adjustment to 2023). For more information see NOAA’s National Centers for Environmental Information overview on Billion-Dollar Weather and Climate Disasters (NCEI, n.d.-a). 3 Frontline communities include “people who are both highly exposed to climate risks (because of the places [in which] they live and the projected changes expected to occur in those places) and have fewer resources, 18 PREPUBLICATION | UNCORRECTED PROOFS 

which is exacerbating chronic environmental stressors and driving the intensification of dangerous storms and other extreme weather-climate events. 4 In this context, new strategies are essential to enable communities to plan for the increasing risk associated with compounding disasters. STUDY CONTEXT AND CHARGE The Gulf Research Program (GRP) 5 of the National Academies of Sciences, Engineering, and Medicine (the National Academies) sponsored this consensus study to explore factors that enable—or could enable—Gulf Coast communities to prepare for, respond to, mitigate, and recover from disasters more effectively. With the events and lived experiences of the 2-year period 2020–2021 to guide the study, the GRP appointed an ad hoc committee of experts in community resilience; disaster management; public health; and behavioral, social, and atmospheric sciences (Committee on Compounding Disasters in Gulf Coast Communities, 2020– 2021) and asked them to provide findings and conclusions relevant to their task (see Box 1-1 for the committee’s Statement of Task). In an era of rapidly increasing climate-amplified hazards and extreme weather-climate events, it is crucial for policymakers, decision-makers, and communities to understand how impacts associated with disruptive events and chronic stressors interact, exacerbate health disparities and socioeconomic stressors, and inhibit effective or complete disaster recovery. This principle is especially relevant for GOM communities that remain in various stages of recovery from previous disasters, including hurricanes and the lingering effects of the Deepwater Horizon disaster of 2010. These compounding disaster effects undermine the systems and functions of capacity, social or economic safety nets, or political power to respond to those risks. Frontline communities are those that experience the ‘first and worst’ consequences of climate change. These are often, but not limited to, communities of color and low-income communities” (USGCRP, 2023). 4 “Extreme weather-climate event” is a hybrid term used by the committee to describe weather events that are more likely to occur, more intense, longer-lasting, or larger in scale due to climate change. See Chapter 2, Attribution Science and glossary definitions for Extreme Event, Weather-Related, and Extreme Event, Climate- Related for details. 5 The GRP was established in 2013 with funds from a criminal settlement stemming from the Deepwater Horizon disaster, which occurred in the Gulf of Mexico in 2010. Upon receipt of the settlement funds, the National Academies, through the GRP, was charged with establishing a 30-year program in the public interest focused on offshore energy safety, environmental protection, and human health. In sponsoring this study, the GRP aims to advance scientific understanding, engage networks, and ultimately bridge knowledge to action in accordance with its primary strategic goals. 19 PREPUBLICATION | UNCORRECTED PROOFS 

many GOM communities, making them more vulnerable to experiencing future disruptive events as disasters. Referenced throughout this report, the committee calls attention to the need for strengthening the adaptive capacity of vulnerable and exposed communities. Simply defined, adaptive capacity is the relative ability of systems, institutions, and humans to adjust to potential damage, to take advantage of opportunities, or to respond to consequences (USGCRP, 2023). Enhancing adaptive capacity includes a range of strategies and actions, explored in greater detail throughout this report. It should be noted that, although this study focuses on a particular geographic region, it is the committee’s hope and intention that its findings and conclusions will inform national and international dialogues on disaster risk reduction, with an emphasis on the imperative to improve daily living conditions in at-risk communities, particularly those with high exposure and vulnerability and low adaptive capacity. BOX 1-1 Statement of Task A committee of the National Academies of Sciences, Engineering, and Medicine will document the impact and lessons learned from multiple, compounding disasters that occurred across the Gulf Coast region in 2020–2021. Within this 2-year period, Gulf of Mexico communities experienced numerous billion-dollar extreme weather disasters, widespread energy infrastructure failures and the COVID-19 pandemic. These events occurred against a backdrop of persistent social and economic inequities, resulting in disproportionate impacts of these events on historically marginalized, disadvantaged, and excluded groups. The increasing frequency or severity of extreme weather events, amplified by climate change, will likely continue to exacerbate these impacts on the resilience of communities throughout the Gulf region. This committee will: ● Describe the major disasters that occurred in the Gulf region during the 2-year period and, to the extent known, their impacts on community markers such as local economies, government functions, industry, the education system, human health, social structure. ● Discuss how these effects were compounded due to the sequencing of events as well as the factors that may have amplified these impacts (e.g., poverty, health disparities, economic and governance constraints, obsolete or inadequate infrastructure). 20 PREPUBLICATION | UNCORRECTED PROOFS 

● Identify lessons learned from and needs exposed in how communities dealt with compounding disasters. ● Provide findings on what factors enabled or could enable communities to successfully plan for, respond to, recover from, and mitigate the impacts of compounding disasters. 21 PREPUBLICATION | UNCORRECTED PROOFS 

STUDY APPROACH The topic of compounding disaster impacts and recovery is complex, and many applied research questions regarding strategies, solutions, and governance remain outstanding (NASEM, 2022a). With nascent research on this topic, particularly within the context of the GOM during the 2020–2021 period, the committee emphasized qualitative, primary data collection through information-gathering sessions with key informants in the GOM and the review of locally generated after-action reports and other primary and secondary sources as its approach to the statement of task. These learnings were then contextualized within relevant scientific literature, including completed National Academies consensus study reports, to support the development of the committee’s findings and conclusions. This method allowed the committee to meet its task by applying the evidence base and documenting the effects of compounding disasters in a specific region within a specific time frame, from the lived experience, knowledge, and assessments of those affected. The committee was not tasked with offering recommendations. The committee conducted information gathering from key informants and subject-matter experts for this study from January 2022 through April 2023. Deliberations among committee members continued throughout the information-gathering and report development process and concluded in spring 2024. The committee’s work was informed by 13 in-person public information-gathering sessions held over 6 days in three locations, four virtual public sessions, a review of relevant scientific literature, and two commissioned papers. Virtual Information-Gathering Sessions The committee convened four virtual information-gathering sessions between December 2022 and April 2023 to gain perspective on several topics, including housing and disaster-related displacement; meteorological, atmospheric, and oceanographic influences on extreme weather- climate events; state and municipal chief resilience officers; and experiences of disaster-affected community stakeholders outside of the in-person sessions. All virtual information-gathering sessions were public. Agenda and participant listings are included in Appendix B. 22 PREPUBLICATION | UNCORRECTED PROOFS 

Regional, In-Person Information-Gathering Sessions The committee’s choice of regional locations in which to hold information-gathering sessions was based on the states where multiple disruptive events significantly affected community functioning during the 2020–2021 time frame. While recognizing that disruptive events and disasters occurred in many communities throughout the GOM region, the committee ultimately selected for its analysis of compounding disaster experiences three representative GOM areas to conduct information gathering. 6 Together, these selections reflect the committee’s priorities in seeking a range of compounding disaster experiences across GOM states with varying demographics, capacities, and experiences contending with disasters. In October 2022, the committee convened five in-person information-gathering sessions in Houston, Texas, with participants who work and/or reside in Harris or Galveston County. In December 2022, the committee convened four in-person public information-gathering sessions in Lake Charles, Louisiana, with participants who work and/or reside in Calcasieu or Cameron Parish. In January and February 2023, the third and final set of four in-person public information-gathering sessions was held in Mobile, Alabama, with participants who work and/or reside in Mobile or Baldwin County. In-person sessions included representatives from state and local government; federal agencies; and faith-based, community-based, and nongovernmental organizations involved in various aspects of disaster risk management. These experts were invited to share their personal and professional experiences and perspectives on the impacts of and interconnections among disasters and on lessons learned, forgotten, and applied, as well as policy and practice considerations related to compounding disasters in GOM states between January 2020 and December 2021. All in-person information-gathering sessions were public. Agenda and participant listings are included in Appendix B. The primary data elicited from session participants in the information-gathering sessions formed the basis of the report’s summary, analysis, findings, and conclusions. 6 Counties in Mississippi and Florida were not selected for in-person visits because of the absence of both weather-climate and hazard events with widespread impacts that significantly affected community functioning in the 2020–2021 time frame. At times, data from these states are included in the report for contextual purposes. 23 PREPUBLICATION | UNCORRECTED PROOFS 

Methodological Limitations to In-Person Information-Gathering Sessions The committee aimed to hear from a diverse array of representatives involved in the weather-climate event and disaster space. This approach is not without limitations. Time, resources, location, availability, residency, the particular dynamics and composition of attendees for each session, comfort levels of participants in sharing their experiences and perspectives with the committee or among their professional peers, the number of panelists, and their loquaciousness and interest in particular topics all shaped the information gathered. Coordinating speakers for the information-gathering sessions also depended on representatives’ availability. Panelists who participated in these sessions also still lived and worked in the GOM region, and their perspectives and experiences may differ from those who opted to leave or were displaced by the disasters. Despite these potential biases and limitations, the insight gained from these sessions formed the basis for the committee’s understanding of what it was like to live in the GOM region during this tumultuous period and how recovery has since progressed. Primary and Secondary Sources At the outset of its deliberations, the committee worked in collaboration with the National Academies Research Center to develop and carry out a review of the relevant literature to support its work and provide additional scientific evidence to inform this report and the committee’s findings and conclusions. The committee also conducted literature searches to identify contemporaneous news articles as well as peer-reviewed and gray literature related to compounding disasters and associated impacts in GOM states within the 2020–2021 time frame. After-Action Reports It is common for government bodies to assemble “after-action” or “action” reports in the wake of disasters. Responding agencies such as the Federal Emergency Management Agency (FEMA), their local counterparts, and the National Oceanic and Atmospheric Administration 24 PREPUBLICATION | UNCORRECTED PROOFS 

(NOAA) seek to identify both successes and failures in disaster preparations and responses. The U.S. Department of Housing and Urban Development requires recipients of disaster recovery grants to prepare action plans that specify how dollars will be spent and best practices for recovery. These reports provide systematic reviews of how government agencies responded to disasters and how they might learn from any inadequate responses. The committee conducted a systematic search for such reports and reviewed them for specific practices that reflected lessons learned during 2020–2021. This report discusses after-action reports produced by the state of Louisiana, the city of Houston, and the state of Alabama. Additionally, several information- gathering session participants from government agencies participated in the production of these reports. Commissioned Papers The committee commissioned two papers to supplement its information-gathering sessions (see Appendix C). The first paper, “Compounding Disasters in Gulf Coast Communities 2020–2021: Impacts, Findings, and Lessons Learned in Jefferson Davis and Marion Counties, Mississippi,” produced by Dr. Jennifer Trivedi, examines the physical, social, and economic factors contributing to the realized impact of multiple disasters within Jefferson Davis and Marion Counties, Mississippi, where the committee did not conduct a site visit or hold in-person information-gathering sessions, but where social vulnerabilities are significant. This paper also seeks to identify physical, social, and economic factors that may reduce the impacts of future disasters in these two counties. The second paper, “How a Changing Societal Landscape Is Shaping Gulf Coast Tropical Cyclone and Tornado Disasters,” produced by Dr. Stephen Strader, addresses physical and social factors contributing to the realized impact of multiple disasters within the particular geographic areas of interest for this study: Houston and Galveston Counties, Texas; Cameron and Calcasieu Parishes, Louisiana; and Mobile and Baldwin Counties, Alabama. Jefferson Davis and Marion Counties, Mississippi, were also included in the analysis. 25 PREPUBLICATION | UNCORRECTED PROOFS 

CONCEPTUALIZING COMPOUNDING DISASTERS Drawing on existing frameworks derived from disaster scholarship, the committee began its inquiry by examining the conventional Venn diagram that contemplates disaster risk as the product of intersecting hazards, exposure, and vulnerability, as illustrated by Figure 1-1. FIGURE 1-1 Disaster risk as a product of intersecting hazards, exposure, and vulnerability. SOURCE: Adapted from Figure 19-1 in M. Oppenheimer, M. Campos, R. Warren, J. Birkmann, G. Luber, B. O’Neill, and K. Takahashi, 2014: “Emergent risks and key vulnerabilities”; in Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, C. B. Field, V. R. Barros, D. J. Dokken, K. J. Mach, M. D. Mastrandrea, T. E. Bilir, M. Chatterjee, K. L. Ebi, Y. O. Estrada, R. C. Genova, B. Girma, E. S. Kissel, A. N. Levy, S. MacCracken, P. R. Mastrandrea, and L. L. White, eds.. Cambridge University Press, United Kingdom and New York, pp. 1039–1099. Within each of these lenses lie numerous layered and interrelated drivers of risk. For the purposes of this report, the committee adopted the use of the following definitions: ● Hazards are understood to be processes, phenomena, or activities with the potential to “cause loss of life, injury or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems, and environmental resources” (USGCRP, 2023). Hazards may be natural or human-made and can occur individually or 26 PREPUBLICATION | UNCORRECTED PROOFS 

simultaneously. Examples of hazards reflected in this study include severe and extreme weather-climate events and the global COVID-19 pandemic. ● Vulnerability encompasses social and economic sensitivities of individuals and groups, along with deficiencies in the structures and systems on which they rely, and that reduce their capacity to withstand hazards. Vulnerable communities are those least able to anticipate, cope with, and recover from disruptive events. ● Exposure describes the presence of people, infrastructure, housing, production capacities, and other tangible human assets in hazard-prone geographies or situations. ● Disaster risk is expressed as a product of hazard, exposure, and vulnerability variables and understood as the potential for loss of life, injury, physical damage or destruction resulting from the occurrence of one or more disruptive events in a given period. Accordingly, realized disaster impacts are products of not only the severity or intensity of the hazard itself but also the combination of vulnerability and exposure—or sensitivity—of the community and its underpinning systems and functions to suffer loss and damage. Many communities in the GOM region exist in a state of heightened disaster risk and perpetual recovery. As a result, the community’s systems and functions are progressively diminished. From a humanitarian perspective (UNHCR, 2024), the immediate, visible, and experiential effects of disasters cannot be decoupled from the preexisting conditions of exposure and vulnerability that produce sensitivity to the event while increasing sensitivity and risk to future events. As such, the disaster management enterprise must be responsive to the occurrence of singular and multiple disruptive events but also of the persistent societal conditions that create sensitivity to future disasters and compose the epoch nature of the compounding effects of disasters within disaster survivors’ lives. To guide its exploration of this topic, and for the purposes of this study, the committee characterizes a compounding disaster as the result of overlapping, concurrent, or successive disruptive events that affect the societal, governmental, and/or environmental functions of a community or region and diminish the community’s capacity to recover and resume essential activities. The weakening of these interrelated functions 27 PREPUBLICATION | UNCORRECTED PROOFS 

inhibits and prolongs the disaster recovery period, making communities more likely to experience amplified negative effects of future disruptive events. Some communities are at disproportionate risk of suffering the effects of compounding disasters as a result of the interplay of persistent physical and social vulnerability factors and increased exposure to climatic and non- climatic hazards. There is nothing linear about the movement of hazards, exposure, vulnerability, and risk variables. Through its deliberations, the committee found the classic Venn diagram (depicting hazards, exposure, vulnerability, and resulting risk) constrained in its representation of the dynamics and variables associated with compounding disasters. The common definitions of hazard, exposure, vulnerability, and risk remain accurate, yet the ways that risk compounds and grows requires a more integrative visualization, as depicted in Figure 1-2. The interaction and agitation within hazards, exposure, vulnerability variables, and the resulting risk is more dynamic and complex. To help visualize this complex interaction, the committee developed a conceptual illustration, Figure 1-2. FIGURE 1-2 Conceptual illustration of compounding disaster risk. SOURCE: Image provided courtesy IBHS. 28 PREPUBLICATION | UNCORRECTED PROOFS 

The scenario illustrated in Figure 1-2 represents multiple hazards that are propelled into interconnected societal mesh. The mesh represents the interwoven dimensions of exposure and vulnerability that largely influence the lived experience within a community and its sensitivity to overlapping, concurrent, or successive disruptive events caused by one or more hazards. The planes, or platforms, on which vulnerability and exposure variables are layered, are pushed upward into a deepening red zone by the occurrence of hazards, resulting in increased compounding disaster risk and heightened sensitivity to the occurrence of future disruptive events. In this example, the platforms for exposure and vulnerability are not equal, nor are the variables stacked upon them. In reality, the levels of exposure and vulnerability are unique to each community and dynamic in both space and time. Exposure to hazards increases or decreases through numerous variables, including land development patterns, housing realities, infrastructure location and functionality, and climate-driven changes within the physical environment. Vulnerability increases or decreases through socioeconomic strength and stability, health care and education access and quality, and social capital, among others. Exposure and vulnerability are inextricably linked and influenced by choices made by individuals, families, community leaders, and policymakers. Long-standing and systemic realities often dominate how exposure and vulnerability combine to create sensitivity within the context of disasters. As disasters compound, quality of life and the ability to prepare for and recover from future disruptions deteriorates. As described throughout the report, making choices to increase adaptive capacity within community systems may be the most effective way to pull down risk by intentionally reducing exposure and vulnerability. Shared Compounding Disaster Experiences in the Gulf of Mexico Region At the committee’s information-gathering sessions, participants from the GOM region expressed views aligned with findings from numerous recent studies—that when disasters compound, resources become strained, and the preparedness, response, and recovery phases often overlap (Finucane et al., 2020; Knox et al., 2022; Mitchell and Knox, 2021; Singh et al., 2023). Simply, there is not enough time to respond to and recover from the first disruptive event by the time the second (or third) occurs, placing interdependent critical infrastructure systems 29 PREPUBLICATION | UNCORRECTED PROOFS 

and populations at further risk (Wells et al., 2022). As a result, decision-makers face difficult trade-offs when prioritizing recovery of needed services, such as infrastructure repair, debris cleanup, and system restoration (Knox et al., 2022). Compounding disasters also exacerbate and multiply systemic and socially constructed vulnerabilities that subject certain populations to disproportionate disaster impacts (NASEM, 2022a). Participants in the Texas, Louisiana, and Alabama information-gathering sessions shared elements of three overarching and related experiences with compounding disasters: (1) material damage and losses compound, often in unanticipated ways; (2) recoveries interrupted result in extended recovery time lines, and many adverse impacts are compounded by the subsequent event(s); (3) high sensitivity and low adaptive capacity (e.g., low socioeconomic status and poor health outcomes) render individuals and communities more vulnerable to acute disaster impacts and compounded losses, and disadvantaged for long-term recovery. The committee’s engagement across the GOM region pointed to one overarching dynamic that transformed the lived experience of compounding disasters and living conditions within the communities—enhanced adaptive capacity. Referring back to Figure 1-2, risk can be lowered through the enhancement of adaptive capacity. When organized and activated, the people, systems, and institutions possess inordinate abilities to take advantage of opportunities to reduce vulnerabilities, lower exposures, and bend their response to disasters toward recovery and better outcomes. CONTEXT AND FRAMEWORK FOR COMPOUNDING DISASTERS While research on compound(ing) risks, events, and disasters is a rapidly growing field, many applied research questions regarding strategies, solutions, and governance remain outstanding (NASEM, 2022a). To inform some of these gaps from both multidisciplinary and empirical perspectives, the committee hopes to offer a more nuanced understanding of the realized effects of compounding disasters within a particular region and timescale. In addition, and as identified by the Fifth U.S. National Climate Assessment, released in November 2023, this report further explores the “intersection of climate hazards with other environmental hazards like . . . pandemics, or socioeconomic stressors like poverty and lack of adequate housing that disproportionately impact overburdened communities, thereby deepening existing societal 30 PREPUBLICATION | UNCORRECTED PROOFS 

inequities” and hindering the ability and capacity of such communities to “respond and cope” (Singh et al., 2023). Because of climate change, evolving and dynamic weather patterns, and other emergent threats, the risks associated with disruptive events and disasters are also evolving. Drivers of climate change risk are creating new risks and exacerbating existing ones (Simpson et al., 2021). Disruptive events and disasters, especially if occurring in rapid succession, change the severity of risk and impact recovery in often unpredictable ways. Disasters and disruptive events and their residual impacts are complex, interconnected, long-term phenomena that transcend temporal and spatial boundaries, cascading and compounding across sectors and regions (Lukasiewicz and O’Donnell, 2022). The compounding disasters of 2020–2021 in the GOM region created conditions that modified, via a compounding process, the impacts of the disasters that followed. For example, the impacts of Hurricane Laura, which made landfall on August 27, 2020, in Cameron Parish, Louisiana, were and continue to be disruptive, affecting a population and region already grappling with longer-term stressors such as inadequate housing, high unemployment, economic shocks, insufficient health care staff, and a pandemic. The hurricane winds tore off roofs, smashed windows, ripped out power lines and poles, flooded buildings, and overall caused widespread property and infrastructure damage. When Hurricane Delta arrived 5 weeks later it reexposed and reflooded buildings and homes in various states of disrepair. The additional water and wind damages created more complex insurance and federal assistance claims scenarios that event-based reporting systems were ill- equipped to handle, resulting in delays in the flow of resources to municipalities and households alike, further disrupting livelihoods, social connections, health, and education. Less than 5 months later, Winter Storm Uri 7 froze the tarps on roofs, prompting another round of retarping; pipes froze and burst, but went unreported because many residents were still evacuated. Municipal water pressure remained low, and remaining residents went without running water for almost a week. These stressors intensified the risk of disaster impacts for all residents, but exponentially intensified risk for populations with high exposure and vulnerability. Exhaustion, anger, and emotional numbness continued to compound the mental health of residents and was 7 This report uses the term “Winter Storm Uri,” but the committee acknowledges that no official U.S. agency names winter storms. The name “Uri” is a construct of a private media company associated with the Weather Channel. 31 PREPUBLICATION | UNCORRECTED PROOFS 

put to test again when extreme rainfall flooded the area all over again 3 months later. Debris not yet removed from the 2020 storm sequence clogged stormwater systems, limiting the capacity available to absorb or drain the record rainfall. As a state official noted: “You don’t have a break. It just keeps hammering.” These increased complexities warrant an evolution of our understanding of disasters, particularly as it pertains to disaster recovery, which typically cannot be measured in months, but rather in years, decades, or even lifetimes. Increased Risk of Compounding Disasters in the Gulf of Mexico Region Climate change will continue to affect every region on Earth in a multitude of ways, with adverse impacts such as the severity, duration, and frequency of extreme weather-climate events increasing in the coming years (IPCC, 2021, 2022; USGCRP, 2023). Humans, animals, plants, and the ecosystems they inhabit will experience longer, hotter heat waves; longer summers and shorter winters; and intensification of the water cycle, accompanied by flooding and more intense rainfall in some regions and drought in others (USGCRP, 2023). Seas will continue to warm and rise, increasing the likelihood that hurricanes will continue to intensify, with damaging winds, and life-threatening storm surge. Climate change can also increase the probability of pandemics like COVID-19 and exacerbate their impacts (Ernst et al., 2023). Accordingly, climate change is an omnipresent, direct and indirect, threat to population health. During 2020–2021, two phenomena—the COVID-19 pandemic and climate change— were shaping disaster risk worldwide, with particularly severe consequences in the GOM region. The emergence and spread of COVID-19 transformed the public health risk of all other extreme weather-climate events by amplifying health-compromising exposures and underlying vulnerabilities in the region. The pandemic also modified preparedness, response, and recovery procedures for the 2020–2021 weather-climate events. The combined result was a complex and unprecedented public health and socioeconomic crisis—an exemplar of compounding disasters. Disasters are the instantiation of risk and are largely a social construct, influenced by human choices, priorities, and values (Oliver-Smith, 2022). Oftentimes, a natural hazard (e.g., a hurricane) is conflated with the impact the hazard can have when it intersects with vulnerable and exposed people and deemed to be a “natural disaster.” Accordingly, the disasters discussed 32 PREPUBLICATION | UNCORRECTED PROOFS 

in this report are not referred to as natural disasters, despite the widespread use of that term. A hazard may be natural in origin and further amplified by human-caused climate change, but a disaster is characterized by the exposure and vulnerability of people and places rather than the hazard itself. The combination of climate-intensified hazards, a low-lying coast with major population centers, poor health outcomes, and degraded infrastructure result in high exposure and vulnerability within the GOM region, and are just several factors that make residents particularly susceptible or sensitive to disasters and even more so to compounding disasters (Burton, 2010; O’Keefe et al., 1976; Steinberg, 2000). Compound(ing) Disaster Literature and Impacts in the Gulf of Mexico Region The convergence of climate change and the global COVID-19 pandemic in 2020 further complicated conventional conceptualizations of disasters, spurring more publications relating to compound disaster events in the United States and globally. While disaster science has advanced in recent years, an understanding of the interrelatedness, connections, and complexities of exposures, vulnerabilities, and adaptive capacities that can determine the scale of compounding disasters diverges among disciplines and remains largely siloed (Kruczkiewicz et al., 2021). A growing list of related terms—including complex, simultaneous, concurrent, parallel, cascading, cumulative, multihazard, domino, conjoint, multivariate, preconditioned, connected, compound, and catastrophic—continues to be used in the literature to describe disaster events without agreement on their definitions (Cutter, 2018). The literature on compounding risks, events, and disasters, inclusive of the multiple terms and conceptualizations, can provide a broader scientific context for the study and its findings and conclusions. As sea level rise, drought and other long-term stressors challenge conventional notions of a disaster, researchers are calling for more attention to gradual-onset effects (Tosun and Howlett, 2021; Yamori and Goltz, 2021) as well as to expand theoretical examinations of extreme event(s) attribution (Zscheischler and Lehner, 2022) and empirical evidence of compounding disasters’ associated health threats, particularly for vulnerable populations (Ebi, et al., 2021; Gao and Wang, 2023; de Ruiter et al., 2020; Singh et al., 2023). Repeated exposure to hurricanes can prompt an increase in mental health symptoms (Garfin et al., 2022), while anxiety and stress may 33 PREPUBLICATION | UNCORRECTED PROOFS 

develop in individuals experiencing cumulative fatalities/injuries from multiple disasters (Hu et al., 2021). Cascading disasters, such as Winter Storm Uri and the power grid failure, led to increased thoughts of suicide (Sugg et al., 2023). Simpson and colleagues (2021) propose a risk assessment that incorporates a holistic view of climate change risks that recognizes mitigation and adaptation responses as potential risk drivers and that considers risk interactions (e.g., how multiple risks aggregate, compound, and cascade). Others are urging scholars and practitioners to integrate “multi-hazard thinking” or “compound thinking” into risk assessments, emergency management response plans, mitigation policies, and postdisaster settlement planning (Lee et al., 2024; Tsai et al., 2021; van den Hurk et al., 2023), as well as incorporating local and traditional knowledge (Nakashima et al., 2018). The experiences of many GOM residents in 2020–2021 echoed many of the complexities described in the literature, confirming the evolution of the increasingly entangled nature of compounding disasters and the inadequacy of current disaster response and recovery approaches within the disaster management enterprise. Complexities that were experienced ranged from incompatible response protocol (e.g., biological versus weather-related hazards; Potutan and Arakida, 2021); interactions between risks of transboundary climate extremes and slow-emerging climate change effects (e.g., sea level rise; Harris et al., 2022); attribution of direct/indirect disaster mortality counts that further complicated postdisaster mortality surveillance (NASEM, 2020; Santos-Lozada and Rivera- Reyes, 2024); and disaster experiences that produce compound disadvantages that accumulate across domains, resulting in a “multiplicity of impact” (Priest and Elliot, 2023). Overlapping, Interrupted, and Prolonged Recoveries In the GOM region, disaster recovery is a process that is unbound by time. Communities with high levels of social and economic vulnerabilities are more likely to experience prolonged or indefinite disaster recovery periods (e.g., disposal of improperly remediated disaster debris near low-income neighborhoods; Allen, 2007) and ongoing mental health impacts (Cherry et al., 2021) during which time their sensitivity to experience the onset of each new disruptive event as a disaster is amplified. 34 PREPUBLICATION | UNCORRECTED PROOFS 

In the GOM region, communities are increasingly living under “continuous threat, response, and recovery disaster cycles” (Osofsky et al., 2022; p. 2). In other words, while communities are responding to a disaster, they will also be recovering from a previous disaster (Lukasiewicz and O’Donnell, 2022), blurring the lines between the mitigation, preparedness, response phases, and extending recovery into what more closely resembles an epoch within a disaster survivor’s lifetime. Within this undefined period of perpetual disaster recovery, risk and sensitivity to adverse impacts from a future disaster or disruptive event are heightened. When multiple disasters overlapping in space and time occur, with residual effects persisting and the recovery time line extending indefinitely, it becomes more difficult to ascribe loss and damage to the occurrence of a particular discrete event. Yet, in seeking disaster recovery assistance from FEMA, applicants are required to submit separate applications for each disaster wherein applicants must “describe what damage happened on which date to ensure you’re applying under the correct disaster” (FEMA, 2024). Just as parsing the physical damage that occurred during each disaster can blur together, recoveries from these disasters also can become indistinct. A nongovernmental organization leader from Harris County explains how he experienced this reality in an information-gathering session: “In my line of work, rebuilding houses, we still haven’t recovered from Harvey— potentially haven’t recovered from the Tax Day and Memorial Day floods in ’14 and ’15. So all that recovery blends together.” The disaster recovery process is nonlinear, contingent on and bound by cultural histories and geographies (Hsu et al., 2015). The associated systems and policies both create and sustain barriers to recovery and the inequitable distribution of resources (Thomas et al., 2020), defined by universal or predetermined, inflexible parameters that can reproduce inequities and deepen vulnerabilities. Thus, while a disruptive event may be bound by a specific temporal time frame of onset and conclusion (e.g., the hurricane has passed or dissipated), the recovery period associated with the aftermath is far more challenging to encapsulate when interrupted by another disruptive event. It is through this lens that the committee sought to understand the factors that position communities, some more than others, to experience the compounding effects of multiple disruptive events and overlapping and interrupting disaster recoveries. 35 PREPUBLICATION | UNCORRECTED PROOFS 

The Rise of Billion-Dollar Disasters During 1980–2023, the costs of billion-dollar disasters in the United States topped $2.6 trillion (see Figure 1-3). Adding to this total the costs attributed to weather-climate events for which damages fell below the billion-dollar threshold could increase this amount by as much as 20 percent (NOAA, 2022b). Every U.S. state and territory is susceptible to costly weather- climate disasters, but three states in the GOM region—Florida, Louisiana, and Texas—currently rank highest in terms of disaster-related costs. Each state incurred more than $200 billion in damages between 1980 and 2023. Figure 1-3 shows total billion-dollar disaster costs by state during this period. Since 1980, Texas has led the nation in total cumulative costs resulting from billion-dollar weather-climate disasters ($402 billion). Florida currently ranks second ($389 billion) but was briefly supplanted by Louisiana ($304 billion) as a result of Hurricane Ida in 2021 (NCEI, n.d.-b; A. Smith, 2022). FIGURE 1-3 Total costs of billion-dollar disasters, 1980–2023, by state. SOURCE: NOAA, 2024. 36 PREPUBLICATION | UNCORRECTED PROOFS 

Adjusting for inflation, billion-dollar disasters are steadily rising in number (NCEI, n.d.- a). In 1980, 3 disasters (all impacting at least one GOM state) met or exceeded the $1 billion threshold, compared with 28 in 2023 (NCEI, n.d.-a). Longitudinal examination of billion-dollar disasters over the decades reveals a steady increase in such events: 33, 57, 67, and 131 in the 1980s, 1990s, 2000s, and 2010s, respectively. In 2020, 22 billion-dollar (or greater) weather- climate disasters occurred in the United States (NCEI, n.d.-c); 17 of these took place in the GOM region (NCEI, n.d.-b). In 2021, 20 such disasters occurred (NCEI, n.d.-c), 15 in the GOM region (NCEI, n.d.-b), together resulting in approximately 950 direct or indirect fatalities (NOAA, 2022b). From January 1, 1980, to September 11, 2023, GOM states experienced 243 billion-dollar disasters (see Figure 1-4), which equates to an annual average of 5.5 such events in that time frame. In the 5-year period from 2019 to 2023, this annual average more than doubles, to 14.6 events (NCEI, n.d.-a). Overall, these 243 disasters resulted in the official, direct deaths of 11,121 residents (NCEI, n.d.-a). During the 2-year span of 2020–2021 GOM states collectively endured 32 billion-dollar disasters, including six hurricanes in 2020 (Delta, Eta, Hanna, Laura, Sally, and Zeta) and in 2021, two tropical storms (Elsa and Fred), two hurricanes (Ida and Nicholas), a major flood event, a hailstorm, and a severe winter storm (Uri). FIGURE 1-4 Type, number, and total cost of GOM states’ billion-dollar disasters, 1980–2023. SOURCE: NCEI, 2023. 37 PREPUBLICATION | UNCORRECTED PROOFS 

Multiple challenges exist when comparing recent and historical billion-dollar disasters. Inflation is one consideration, but increases in population and building activity must also be taken into account. For example, if there were a $700 million event in 2013, adjusting for inflation, that event would not reach the billion-dollar mark today. However, if a disruptive event of the same magnitude as the 2013 event occurred in an area with increased population and building construction, it would likely be deemed a billion-dollar event because of the greater exposure of people and buildings (Theodorou, 2023). Disasters Hidden Beneath the Billion-Dollar Disaster Threshold The federal disaster declarations and billion-dollar designations for the major storms of 2020–2021 do not account for the less well-known or unnamed storms or disruptive events that occurred during those 2 years. Such events contribute to accumulated losses and damage to communities lacking infrastructure and proper mitigative measures—features that often align with vulnerability factors such as income, race, and rurality (Hendricks and Van Zandt, 2021). Geographically limited and lower-magnitude events such as low-scale tornadoes, flooding, and even tropical systems experienced in the GOM region do not meet the threshold of a billion dollars, nor do they receive the attention as major disasters tagged with such superlatives as “deadliest,” “largest,” and “earliest.” Yet, they are disruptive events that can stress communities and their undergirding systems and further prolong recovery periods from previous disruptive events and disasters. In parts of Lake Charles, Louisiana, for example, a heavy rain event in May 2021 produced 12.49 inches of rainfall in 24 hours, 6 inches of which fell in a 2-hour period (Di Liberto, 2021), while many residents were still reeling from 2020’s Hurricanes Laura and Delta and Winter Storm Uri. This was the third-highest amount of rain at one time on record in Lake Charles (Benedict, 2022), and it caused significant flooding, creating obstacles for a region already suffering from compounding disasters. The sensitivities of the affected population elevated the disruptive event to compounding disaster status. The baseline for GOM states—one of extreme risk driven by vulnerability, upon which growing hazard exposure is overlaid—exacerbates the potential for future compounding disasters. Mitigating the effects of such disasters will require addressing the drivers of 38 PREPUBLICATION | UNCORRECTED PROOFS 

vulnerability, exposure and uneven migration, while concurrently increasing understanding of the multiple, interacting risks and responses to climate change (Simpson et al., 2021) and compounding disasters. RELEVANT NATIONAL ACADEMIES REPORTS The National Academies has produced numerous reports focused on strategic planning related to disaster preparedness and on health and resilience related to climate change. A number of these reports are relevant to the work of this committee, and this report builds on the findings, conclusions, and recommendations of those earlier studies. Highlights of these reports are presented in Box 1-2. BOX 1-2 Relevant National Academies Reports In Climate and Social Stress: Implications for Security Analysis (NASEM, 2013), the authoring committee contends that, as the frequency and severity of environmental hazards increase with climate change, the nation will likely begin to see “clusters of apparently unrelated climate events occurring closely in time” and “events in which a climate event precipitates a series of other physical or biological consequences” (p. 3). Such climate events can precipitate social disruptions in both the affected local area and beyond, in some cases causing shocks to global supply chains. The committee concludes that a robust assessment of the likelihood of intersecting threats, coupled with “timely preventive measures” and effective emergency response, will be necessary if the United States is to prevent and respond to potentially catastrophic events (p. 139). In Disaster Resilience: A National Imperative (NASEM, 2012), the authoring committee acknowledges that “disasters will continue to occur . . . in all parts of the country” and that “impacts of climate change and degradation of natural defenses such as coastal wetlands make the nation more vulnerable” (p. 14). The committee recommends that federal agencies incorporate resilience as a guiding principle at all levels and that both the public and private sectors “work cooperatively to encourage commitment to and investment in a risk management strategy that includes complementary structural and nonstructural risk-reduction and risk-spreading measures or tools” (p. 212). In Healthy, Resilient, and Sustainable Communities after Disasters: Strategies, Opportunities, 39 PREPUBLICATION | UNCORRECTED PROOFS 

and Planning for Recovery (NASEM, 2015), the authoring committee identifies the importance of human health and equity in rebuilding resilient communities after a disaster, stating that “equity, resilience, and sustainability are all relevant to post-disaster efforts to build healthier communities’’ (p. 52). The committee specifically recommends that health considerations be integrated into disaster recovery plans at the local, state, and federal levels. Additionally, the committee identifies access to “affordable, high-quality, and location-efficient housing” as an essential element of any healthy community (p. 51). The committee specifically discusses the necessity of (re)building public and accessible housing suited to low-income, elderly, and disabled community members in order to create equitable disaster recovery. In Attribution of Extreme Weather Events in the Context of Climate Change (NASEM, 2016), the authoring committee attempts to elucidate the extent to which an “individual event’s magnitude or probability of occurrence” can be attributed to anthropogenic climate change (p. 2). According to the committee, while it is usually not possible to conclude definitively whether anthropogenic climate change caused an individual weather event, evidence suggests that climate change has influenced the frequency and severity of contemporary heatwaves, heavy rainfall, consecutive dry days, droughts, tropical cyclones, and other extreme events. For more information on attribution science, see the “Hazards” section of Chapter 2 of that report. In Building and Measuring Resilience: Actions for Communities and the Gulf Research Program (NASEM, 2019a), the committee catalogs and evaluates the various efforts to measure community resilience in the Gulf of Mexico (GOM) region and offers suggestions for communities to build their community resilience according to the metrics identified. The committee first identifies six types of community capitals that can provide a holistic view of resilience: natural (or environmental), built (or infrastructure), financial (or economic), human and cultural, social, and political (institutional or governance; pp. 15–16). The committee suggests that communities should take four “key actions” to build their resilience: “1. Build community engagement and buy-in, 2. Account for communities’ multiple dimensions, 3. Link community resilience measures to decision making, and 4. Create incentives for measuring resilience” (p. 60). The committee concludes that community decision- makers must work alongside researchers in longitudinal research and resilience planning to develop resilience initiatives that will result in long-term success. In A Framework for Assessing Mortality and Morbidity After Large Scale Disasters (NASEM, 2020), the authoring committee describes the current challenges with accurately assessing and reporting mortality and morbidity following large-scale disasters and offers recommendations to improve mortality and morbidity data collection and reporting after disasters. According to the committee, two 40 PREPUBLICATION | UNCORRECTED PROOFS 

components of the problem with postdisaster mortality and morbidity reporting are that (a) there are multiple and complex health outcomes that can result from disasters and (b) there is no one measure to quantify the impact of every disaster, and a singular death toll cannot capture the full scope of disaster health impacts. The committee recommends that the U.S. Department of Health and Human Services not only count direct disaster fatalities, but should also work with communities to calculate individual count and population-level estimates of postdisaster mortality and morbidity that distinguish between direct deaths or morbidities, indirect deaths or morbidities, partially attributable deaths and morbidities, and unrelated deaths and morbidities, which are defined in the report (p. 170). In “Opinion: Compound Risks and Complex Emergencies Require New Approaches to Preparedness,” Kruczkiewicz and colleagues (2021) describe how the COVID-19 pandemic has further complicated response to acute disaster events. The authors identify the problem thusly: The ability to anticipate and respond is constrained by a lack of available resources at the right place at the right time, limited governance and accountability, and an underestimation of uncertainty in forecasts for both climate and societal impacts, including social, economic, political, and infrastructural. The COVID-19 crisis further decreases disaster resilience and thus increases baseline risk and the potential scale of impacts on systems, lives, and livelihoods, which in turn increases vulnerability to future disasters. (p. 3). The authors argue that “flexible funding mechanisms and strategies” distributed among “diverse cooperative networks” of stakeholders will be essential to allow communities to plan for and recover from multiple concurrent hazards and disaster events effectively (p. 4). In Resilience for Compounding and Cascading Events (NASEM, 2022a), the authoring committee describes a “new normal” in which disasters occur in rapid succession, “often unleashing new devastation on a community before it has had a chance to recover from the prior disaster” (p. 3). The committee acknowledges that climate change makes the occurrence of compounding disasters increasingly likely. The committee calls for more extensive research on compounding and cascading disasters to help “develop solutions and avoid unintended consequences” that might occur within the current model of emergency management (p. 25). In Engaging Socially Vulnerable Communities and Communicating About Climate Change– Related Risks and Hazards (NASEM, 2022b), the authoring committee writes that socially vulnerable populations are especially vulnerable to the impacts of extreme weather-climate events: 41 PREPUBLICATION | UNCORRECTED PROOFS 

It is important to recognize that information and communication are asymmetrical, and vulnerable groups—including pregnant people, children, older adults, immigrant groups, Indigenous peoples, low-income communities, communities of color, people with disabilities, vulnerable occupational groups (e.g., workers who are exposed to extreme weather), and people with preexisting or chronic medical conditions, among others—often suffer from a comparative lack of authoritative information (American Public Health Association [APHA], 2022; USCRP, 2018). The extreme weather events exacerbated by climate change also often have disproportionate impacts on the above vulnerable populations (APHA, 2022; Dietz, Shwom, and Whitley, 2020; IPCC, 2022; Jacobs, 2019; Méndez, Flores-Haro, and Zucker, 2020; USGCRP, 2018). Among these impacts are psychological distress; physical impairments; and loss of income, property, and livelihood (Wong-Parodi, 2020). Moreover, extreme weather events exacerbated by climate change can compound existing vulnerabilities and inequities experienced by these populations, stemming from past and present structural and systemic discriminatory practices that can limit the ability of communities to adapt (Chen et al., 2022; Jacobs, 2019; USGCRP, 2018) (pp. 2–3). The committee suggests that, to communicate more effectively with socially vulnerable populations, decision-makers should “form partnerships with trusted and diverse community organizations,” (p. 4) develop a structured decision-making process between community members and policymakers, address the social vulnerabilities that cause such inequities, and “allow and encourage community ownership and leadership of responses” (p. 6). In Advancing Health and Resilience in the Gulf of Mexico Region: Roadmap for Progress (NASEM, 2023), the authoring committee identifies the GOM region as especially socially and ecologically vulnerable and describes the need for more effective ways to meet community needs: The Gulf of Mexico region, in particular, suffers from recurrent disasters that have reduced its physical infrastructure, separated communities from resources, and exacerbated the challenges required to deliver the right services, in the right place at the right time, and in the ways that are most beneficial to the communities. The development 42 PREPUBLICATION | UNCORRECTED PROOFS 

of a holistic, systems approach to meeting the health and community resilience needs of people living in the Gulf region will be dependent on a planful and deliberate effort that aligns the service delivery needs with both appropriate investments in physical infrastructure and the human and material resources necessary to carry it out, with appropriate accountability and sustainability built in (pp. 100–101). The committee provides several recommendations directed at research funders and state and federal partners on how to develop more holistic methods for advancing health and resilience in GOM communities, including designing resilience initiatives around community needs with community participation; engaging local community members in research opportunities; and promoting “health in all domains,” such as “mental health care, education, housing, and social infrastructure” (p. 107). Finally, in Community-Driven Relocation: Recommendations for the U.S. Gulf Coast Region and Beyond (NASEM, 2024), the authoring committee chronicles the history and contends with the present reality of communities affected by acute and chronic impacts of climate change, particularly sea level rise and flooding. The committee examines the experience of socioeconomically vulnerable and marginalized communities and offers recommendations for addressing more equitably the priorities and needs of those who have been or may be displaced from their homes in pursuit of greater physical safety. ORGANIZATION OF THE REPORT This report is intended for an audience of decision-makers at the institutional and community levels interested in expanding their understanding of the impacts of compounding disasters on communities; how and why effects compound and amplify; and what factors enabled or could enable communities to successfully plan for, respond to, recover from, and mitigate the impacts of compounding disasters. Chapter 2 describes the disaster risk profile of the GOM region and lays out GOM hazards and baseline exposure and vulnerability conditions, including factors that amplified the impacts of compounding disasters in 2020–2021. Chapter 3 provides an account of the 2020– 2021 compounding disasters and summarizes some of what the committee heard in the public information-gathering sessions in Harris and Galveston Counties, Texas; Calcasieu and Cameron Parishes, Louisiana; and Mobile and Baldwin Counties, Alabama as it relates to participants’ 43 PREPUBLICATION | UNCORRECTED PROOFS 

experiences of compounding disasters. Chapter 4 uses a systems approach to analyze how the effects of compounding disasters interacted with the interconnected and interdependent systems critical to societal functioning, as well as connective factors that may have amplified those impacts. The committee selected this approach because it offers an integrative framework with which to disentangle underlying and emerging patterns, relationships, causality, and feedback loops involved in the 2020–2021 disasters (e.g., the COVID-19 pandemic’s co-occurrence with other disruptive events). Chapter 5 summarizes and examines lessons recognized, learned, and implemented, during the 2020–2021 time frame, in addition to lessons learned and lost from prior disasters. Throughout the narrative content of each chapter, significant committee findings are identified in bold typeface. A summary of findings is also provided at the conclusion of each chapter. Finally, Chapter 6 presents the committee’s conclusions as to the factors that enabled or could enable communities to successfully plan for, respond to, recover from, and mitigate the impacts of compounding disasters. 44 PREPUBLICATION | UNCORRECTED PROOFS