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Disasters by Design: A Reassessment of Natural Hazards in the United States

Disasters by Design

A Reassessment of Natural Hazards in the United States

University of Colorado at Boulder

with the contributions of participants in the
Assessment of Research and Applications on Natural Hazards


Washington, D.C. 1999

The Joseph Henry Press, an imprint of the National Academy Press, was created with the goal of making books on science, technology, and health more widely available to professionals and the public. Joseph Henry was one of the founders of the National Academy of Sciences and a leader of early American science.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for the project.

Library of Congress Cataloging-in-Publication Data

Mileti, Dennis S.
     Disasters by design : a reassessment of natural hazards in the
United States / Dennis S. Mileti
          p. cm. (Natural hazards and disasters)
     Includes bibliographical references and index.
     ISBN 0-309-06360-4 (alk. paper)
     1. Emergency management--United States. 2. Disaster
relief--United States. 3. Natural disasters--United States. 4.
Hazardous geographic environments--United States. 5. Sustainable
development--United States. I. Title. II. Series.
     HV551.3 .M55 1999                         99-29511
     363.34'0973ddc21                           CIP

Copyright 1999 by the National Academy of Sciences. All rights reserved.

Printed in the United States of America.

Contributing Authors

    Christopher R. Adams, Colorado State University

    Daniel Alesch, University of Wisconsin at Green Bay

    James Ament, State Farm Fire and Casualty Co.

    Jill Andrews, University of Southern California

    Norbert S. Baer, New York University

    Jay Baker, Florida State University

    Conrad Battreal, U.S. Army Corps of Engineers

    Timothy Beatley, University of Virginia at Charlottesville

    Stephen O. Bender, Organization of American States

    Philip R. Berke, University of North Carolina at Chapel Hill

    Dennis Black, Colorado State University

    B. Wayne Blanchard, Federal Emergency Management Agency

    Robert Bolin, Arizona State University

    Patricia A. Bolton, Battelle Human Affairs Research Center

    Linda B. Bourque, University of California at Los Angeles

    David Brower, University of North Carolina at Chapel Hill

    William M. Brown, U.S. Geological Survey

    Ian G. Buckle, State University of New York at Buffalo

    Angelia P. Bukley, National Aeronautics and Space Administration

    Raymond J. Burby, University of New Orleans

    Bonnie Butler, Federal Emergency Management Agency

    David L. Butler, University of Colorado at Boulder

    Peggy A. Case, Terrebonne Readiness and Assistance Coalition

    Harold Cochrane, Colorado State University

    Nicolas Colmenares, University of Colorado at Boulder

    Louise Comfort, University of Pittsburgh

    James N. Corbridge, Jr., University of Colorado at Boulder

    Susan L. Cutter, University of South Carolina at Columbia

    JoAnne DeRouen Darlington, Colorado State University

    James F. Davis, California Division of Mines and Geology

    Robert E. Deyle, Florida State University

    John A. Dracup, University of California at Los Angeles

    Thomas Durham, Central U.S. Earthquake Consortium

    Ute Dymon, Kent State University

    Charles Eadie, City of Watsonville at California

    David Etkin, Environment Canada

    Dean C. Flesner, State Farm Fire and Casualty Co.

    Betsy Forrest, University of Colorado at Boulder

    Alice Fothergill, University of Colorado at Boulder

    Steven P. French, Georgia Institute of Technology

    Karen Gahagan, Institute for Business and Home Safety

    Luis A. Garcia, Colorado State University

    David F. Gillespie, Washington University

    David R. Godschalk, University of North Carolina at Chapel Hill

    Joseph H. Golden, National Oceanic and Atmospheric Administration

    Marjorie Greene, Earthquake Engineering Research Institute

    Eve Gruntfest, University of Colorado at Colorado Springs

    Neil Hawkins, University of Illinois at Urbana-Champaign

    Walter Hays, U.S. Geological Survey

    James P. Heaney, University of Colorado at Boulder

    Edward J. Hecker, U.S. Army Corps of Engineers

    Henry Hengeveld, Environment Canada

    Michael Hodgson, University of South Carolina at Columbia

    Ken Hon, U.S. Geological Survey

    Dale Jamieson, University of Colorado at Boulder

    Brian Jarvinen, National Hurricane Center

    Edward Kaiser, University of North Carolina at Chapel Hill

    Jack D. Kartez, University of Southern Maine

    Robert Klein, National Association of Insurance Commissioners

    Howard Kunreuther, University of Pennsylvania at Philadephia

    James F. Lander, University of Colorado at Boulder

    Larry Larson, Association of State Floodplain Managers

    Eugene L. Lecomte, Institute for Business and Home Safety

    Michael K. Lindell, Texas A&M University

    Rocky Lopes, American Red Cross

    George Mader, Spangle Associates

    Enrique Maestas, University of Texas at Austin

    Robert Martin, University of California at Berkeley

    William Martin, ITT Hartford

    Peter J. May, University of Washington at Seattle

    James McDonald, Texas Tech University

    Elaine McReynolds, Federal Emergency Management Agency

    Kishor Mehta, Texas Tech University

    Mario Mejia-Navarro, Colorado State University

    Jerry Mitchell, University of South Carolina at Columbia

    Elliott Mittler, University of Wisconsin at Green Bay

    Jacquelyn Monday, JLM Associates

    Betty Morrow, Florida International University

    John Mulady, United Services Automobile Association

    John-Paul Mulilis, Pennsylvania State University at Monaca

    Susan Murty, University of Iowa at Iowa City

    Mary Fran Myers, University of Colorado at Boulder

    Sarah K. Nathe, California Office of Emergency Services

    David Neal, University of North Texas

    Joanne M. Nigg, University of Delaware

    Stuart Nishenko, Federal Emergency Management Agency

    Franklin W. Nutter, Reinsurance Association of America

    Eric K. Noji, Centers for Disease Control and Prevention

    Charles Nyce, University of Hartford

    Paul W. O'Brien, California State University at Stanislaus

    Robert Olshansky, University of Illinois at Urbana-Champaign

    Robert Olson, Robert Olson Associates, Inc.

    Philip N. Omi, Colorado State University

    Michael J. O'Rourke, Rensselaer Polytechnic Institute

    Risa Palm, University of North Carolina at Chapel Hill

    Eve Passerini, University of Colorado at Boulder

    Edward Pasterick, Federal Emergency Management Agency

    Pamela Pate, University of Texas at Austin

    Robert Paterson, University of Texas at Austin

    Walter Gillis Peacock, Florida International University

    Ronald Perry, Arizona State University

    William J. Petak, University of Southern California

    Jon A. Peterka, Colorado State University

    Brenda Phillips, Texas Woman's University

    John C. Pine, Louisiana State University

    Rutherford H. Platt, University of Massachusetts at Amherst

    Roy S. Popkin, Popkin Associates

    Kenneth W. Potter, University of Wisconsin at Madison

    George Rogers, Texas A&M University

    Richard J. Roth, Jr., California Department of Insurance

    Richard J. Roth, Sr., Consultant

    Claire B. Rubin, Claire B. Rubin & Associates

    David Sample, University of Colorado at Boulder

    Paula Schulz, California Office of Emergency Services

    Stanley Schumm, Colorado State University

    James Schwab, American Planning Association

    Michael S. Scott, University of South Carolina at Columbia

    William Solecki, Florida State University

    John H. Sorensen, Oak Ridge National Laboratory

    Kenneth R. Stroech, U.S. Environmental Protection Agency

    Richard Stuart, U.S. Army Corps of Engineers

    Craig E. Taylor, National Hazards Management, Inc.

    Deborah S. K. Thomas, University of South Carolina at Columbia

    John Tiefenbacher, Southwest Texas State University

    Kathleen Tierney, University of Delaware

    L. Thomas Tobin, Tobin and Associates

    Kenneth C. Topping, Cambria Community Services Department

    Susan K. Tubbesing, Earthquake Engineering Research Institute

    Eric VanMarcke, Princeton University

    Barbara Vogt, Oak Ridge National Laboratory

    Dennis Wenger, Texas A&M University

    James L. Wescoat, University of Colorado at Boulder

    French Wetmore, French & Associates, Ltd.

    David Whitney, California State University at Long Beach

    Berry Williams, Berry A. Williams & Associates

    Leonard T. Wright, University of Colorado at Boulder


  T he nation's first assessment of research on natural hazards got under way in 1972 at the Institute of Behavioral Sciences of the University of Colorado at Boulder. It was an interdisciplinary effort, with an emphasis on the social sciences, funded by the National Science Foundation and led by geographer Gilbert F. White and sociologist J. Eugene Haas. The project involved many graduate students, scholars, practitioners, and policymakers. Their aim was to assess the nation's knowledge of natural hazards and disasters, with an emphasis on the social sciences. Along the way they expected to point out major needed policy directions for the nation and to inventory future research needs. A summary volume issued at the completion of the project (White and Haas, 1975) brought the substance of that knowledge together, analyzed the gaps, and recommended certain policy changes and numerous research needs. (A retrospective look at the impacts of that assessment is presented in Appendix B.)

Contemporary conversations about how sustainable hazards mitigation could result in disaster-resilient communities began in the early 1990s among a few individuals who worked in federal agencies and academia. It was formalized during a workshop in the summer of 1992 in Estes Park, Colorado. Attended by over five dozen of the nation's leading hazards experts, the workshop concluded that it was appropriate to move forward with a second assessment of hazards in the United States and that the unifying theme for the work should be sustainable development.

A subsequent workshop in Boulder, Colorado, in October 1994 brought many of the same people and others together to create a specific agenda for the second assessment. At that time, members of the nation's policymaking arenafor example, the Subcommittees on Natural Hazards and Risk Analysis in the White House and the Federal Emergency Management Agencyexplored the idea of further linking hazards and sustainability. These discussions and the work that followed from them have led to the present volume.

The many experts who contributed to this project started by going to work on the project's formal mission. This was to summarize what is known in the various fields of science and engineering that is applicable to natural and related technological hazards, and to make some research and policy recommendations for the future. The project began with its feet firmly planted in science and engineering, but it ended in an ontological expression. The single most important contribution that this second assessment has to offer is the recommendation for a fundamental shift in the character of how the nation's citizens, communities, governments, and businesses conduct themselves in relation to the natural environments they occupy. This book calls for and speaks to the specifics required to shift the national culture in ways that would stop at its genesis the ever-increasing spiral of losses from natural and technological hazards and disasters. The task will be to create and install "sustainable hazards mitigation" in the culture of the nation.

Disasters by Design does not stop at summarizing the hazards research findings from the past two decades. Instead, it synthesizes what is known and proceeds from that synthesis to outline a proposed shift in direction in research and policy for natural and related technological hazards in the United States.

This book takes a broad focus and occasionally a somewhat speculative tone. It is aimed at a general audience, including policymakers and practitioners. Scholarly readers will note that there are relatively few citations to academic work. This is intentional: first, because the logistics of attempting to cite everything published in the past 20 years would be overwhelming and would increase the manuscript's length by well over 100 pages. The second reason is that this volume comprises synthesized statements of what is known, collectively, about hazards and human coping strategies, which in most cases cannot properly be attributed to a specific source. As a rough way of pointing interested readers toward more information, some citations to the published literature are included at key points in the text. These should not be taken as the authoritative sources on the topics in question but simply as a starting point for more intensive reading. Readers who are interested in viewing the full list of references brought together to support this assessment can find the bibliography on the World Wide Web home page of the Natural Hazards Research and Applications Information Center at

This volume is one in a series published by the Joseph Henry Press that stemmed from the second national assessment on natural and related technological hazards and disasters. The participants in the second assessment's subgroups were invited to write their own books on specialized topics and to have those manuscripts considered for publication as part of the series. The result of those invitations is several additional books in the Joseph Henry Press series. The other volumes cover insurance, organized by Howard Kunreuther and Richard J. Roth, Sr. of the Wharton School; land use, assembled by a team headed by Raymond Burby of the University of New Orleans; disaster preparedness, response, and recovery, assembled by Kathleen Tierney of the Disaster Research Center at the University of Delaware; and a national hazards and risk assessment, led by Susan Cutter at the University of South Carolina. Many other written products have and will emerge from the second assessment, but the Joseph Henry Press book series represents the second assessment's major written products.

The second assessment also resulted in the first new publication series by the Natural Hazards Research and Applications Information Center at the University of Colorado at Boulder, since the center was founded in 1976. The new series is known as the "Natural Hazards Informer." It is designed to summarize in plain language what is known in focused areas of knowledge regarding natural and related technological hazards and disasters. The series is designed to reach local practitioners, and its publication will begin in early 1999. It will be published several times a year by the center in a short newsletter-type format and will be disseminated free to some 15,000 subscribers to the center's newsletter, the Natural Hazards Observer.

Dennis S. Mileti
Boulder, Colorado


  T his project was funded by the National Science Foundation under grant number CMS93-12647 with supporting contributions from the Federal Emergency Management Agency, the U.S. Environmental Protection Agency, the U.S. Forest Service, and the U.S. Geological Survey. The support of these agencies is greatly appreciated. Only the author, however, is responsible for the information, analyses, and recommendations contained in this book. A very special "thank you" is extended to J. Eleonora Sabadell and William A. Anderson of the National Science Foundation for placing their confidence in us to carry out this mission.

Special appreciation is also extended to the persons and the organizations they represent for the time and ideas they contributed as members of the project's advisory panel. Deepest gratitude is expressed to the following persons:

    William A. Anderson, National Science Foundation;

    Michael Armstrong, Federal Emergency Management Agency;

    Riley Chung, National Institute of Standards and Technology;

    Caroline Clarke, National Research Council;

    James F. Davis, California Division of Mines and Geology;

    Walter Hays, U.S. Geological Survey;

    Edward J. Hecker, U.S. Army Corps of Engineers;

    William H. Hooke, National Oceanic and Atmospheric Administration;

    Robert Kistner, Colorado Office of Emergency Management;

    Richard Krimm, Federal Emergency Management Agency;

    Eugene L. Lecomte, Institute for Business and Home Safety;

    James Makris, U.S. Environmental Protection Agency;

    J. Eleanora Sabadell, National Science Foundation;

    James M. Saveland, U.S. Forest Service;

    Kenneth R. Stroech, U.S. Environmental Protection Agency;

    Randall Updike, U.S. Geological Survey;

    Gilbert F. White, University of Colorado at Boulder; and

    Arthur Zeizel, Federal Emergency Management Agency.

Some of the work performed for this assessment was accomplished by subgroups of people who worked on specific topics. Special appreciation is extended to those who coordinated the work of the subgroups.

    David F. Gillespie, Subgroup on the Interactive Structure of Risk;

    Raymond J. Burby, Subgroup on Land Use;

    James P. Heaney and Jon A. Perterka, Subgroup on Engineering;

    Susan Cutter, Subgroup on Risks, Losses, and Costs;

    John H. Sorensen, Subgroup on Prediction, Forecast, and Warning;

    Kathleen Tierney, Subgroup on Preparedness and Response;

    Dennis Wenger, Subgroup on Reconstruction;

    Howard Kunreuther, Subgroup on Insurance; and

    Michael K. Lindell, Subgroup on Adoption and Implementation.

Many professionals were invited in the latter part of 1997 to review the first full draft of the manuscript. The warmest regards and greatest appreciation are extended to the people listed below, who returned their useful and insightful critiques and recommendations for revision of the original draft of the manuscript:

Benigno Aguirre, William A. Anderson, Ken Baechel, Philip R. Berke, Robert Bolin, Pete Brewster, Neil R. Britton, James Bruce, Louise Comfort, Susan L. Cutter, James C. Douglas, Thomas E. Drabek, Russell R. Dynes, David Etkin, Robert Fletcher, Betsy C. Forrest, David F. Gillespie, Joseph Golden, Ruby I. Harpst, Janet C. Herrin, Kenneth Hewitt, Charles W. Howe, Wilfred D. Iwan, Paul Jennings, Steven J. Jensen, Joseph G. Kimble, Gary A. Kreps, Brett Kriger, Howard Kunreuther, James F. Lander, Eugene L. Lecomte, George Mader, Peter J. May, Michael J. McKee, Michael Michalek, William A. Mitchell, Elliott Mittler, Betty Hearn Morrow, John-Paul Mulilis, Mary Fran Myers, Eve Passerini, Dallas Peck, Ray Pena, Roy S. Popkin, E. L. Quarantelli, Richard J. Roth, Jr., Claire B. Rubin, James Russell, Stanley Schumm, Robert L. Schuster, Ellen Seidman, Frank H. Thomas, Kathleen Tierney, Susan K. Tubbesing, James L. Wescoat, Gilbert F. White, John D. Wiener, Ben Wisner, and Arthur Zeizel.

Appreciation is also extended to the people who reviewed and commented on the revised second review draft of the manuscript. These reviewers provided the sharp eyes needed to revise the manuscript into its final form. They brought a variety of perspectives to that review, including national policy, local government, natural science, social science, engineering, the private sector, and nongovernment organizations. Many thanks to the following second-draft reviewers:

Daniel Abrams, Michael Armstrong, Mary Carrido, Jack Cermak, Thomas Drabek, Nicholas Flores, William Hooke, Rocky Lopes, James Makris, Shirley Mattingly, Joanne M. Nigg, Ann Patton, James W. Russell, Randy Updike, and Gilbert F. White.

A very special "thank you" is due JoAnne DeRouen Darlington, who left Colorado State University to join the project staff at the University of Colorado at Boulder, to work as a postdoctoral fellow on this assessment. Her substantive contributions are greatly appreciated as well as her help in providing oversight and leadership for the graduate students who worked on the assessment.

Warm appreciation also goes to David Morton, who lent his patience and willingness to serve as a personal librarian to every contributor to the project.

Finally, literally thousands of pages of original draft text were edited as part of the process to produce this book. Jacquelyn L. Monday edited the manuscript pages in whatever form they arrived, without complaint. Jacki, you will always have my deepest appreciation for the excellent work that you provided as an editor and for your substantive contributions to the text as it emerged over several drafts. Mostly, thank you for taking this project on as your own and for the relentless commitment you brought to it.


  Origins and Development of the Current Approach 18
  Moving Beyond Existing Approaches 24
  Principles of Sustainable Hazards Mitigation 30
  Conclusion 35
  Miami, Florida 42
  Boulder, Colorado 50
  San Francisco, California 57
  Sustainability and Hazards Mitigation 63
  Deaths, Injuries, and Dollar Losses 66
  Other Impacts 90
  Hazard Losses by State 94
  Issues in Loss and Impact Measurement 96
  Future Losses 100
  Data Needs 102
  Conclusion 103
  Systems 106
  The Hazardousness of the Nation 133
  Decisionmaking Processes 136
  Social Influences 144
  Economic Factors 148
  Legal Considerations 149
  Other Influences 152
  Conclusion 154
  Land-Use Planning and Management 155
  Building Codes and Standards 161
  Insurance 166
  Prediction, Forecast, and Warning 174
  Engineering 200
  Conclusion 206
  Disasters 209
  Disaster Preparedness 215
  Response 220
  Factors That Influence Preparedness and Response 226
  Recovery and Reconstruction 229
  Conclusions 239
  New Technology and Approaches 242
  The Research Infrastructure 255
  Education 258
  International Comparisons and Exchanges 261
  Model Communities 264
  Conclusion 265
  One View of Sustainable Hazards Mitigation in Action 268
  Some Policy and Research Steps That Need to Be Taken 274
  A Final Word 287
Appendix A:   Recommendations for Further Traditional Research 297
Appendix B:   Impacts of the 1975 Assessment 315
Appendix C:   Putting Knowledge into Practice 327


  A quarter-century ago geographer Gilbert F. White and sociologist J. Eugene Haas published a pioneering report on the nation's ability to withstand and respond to natural disasters. At that time, research on disasters was dominated by physical scientists and engineers. As White and Haas pointed out in their Assessment of Research on Natural Hazards, little attempt had been made to tap the social sciences to better understand the economic, social, and political ramifications of extreme natural events.

White and Haas attempted to fill this void. But they also advanced the critical notion that rather than simply picking up the pieces after disasters, the nation could employ better planning, land-use controls, and other preventive and mitigation measures to reduce the toll in the first place. Today, at long last, public and private programs and policies have begun to adopt mitigation as the cornerstone of the nation's approach to addressing natural and technological hazards.

The 1975 report also had a profound impact by paving the way for an interdisciplinary approach to research and management, giving birth to a "hazards community"people from many fields and agencies who address the myriad aspects of natural disasters. Hazards research now encompasses disciplines such as climatology, economics, engineering, geography, geology, law, meteorology, planning, seismology, and sociology. Professionals in those and other fields have continued to investigate how engineering projects, warnings, land use management, planning for response and recovery, insurance, and building codes can help individuals and groups adapt to natural hazards, as well as reduce the resulting deaths, injuries, costs, and social, environmental, and economic disruption. These dedicated people have greatly improved our understanding of the physical processes underlying natural hazards and the complexities of social decision making before, during, and after disasters. Yet troubling questions remain about why more progress has not been made in reducing dollar losses.

One central problem is that many of the accepted methods for coping with hazards have been based on the idea that people can use technology to control nature to make themselves safe. What's more, most strategies for managing hazards have followed a traditional planning model: study the problem, implement one solution, and move on to the next problem. This approach casts hazards as static and mitigation as an upward, positive, linear trend.

But events during the past quarter-century have shown that natural disasters and the technological hazards that may accompany them are not problems that can be solved in isolation. Rather, they are symptoms of broader and more basic problems. Losses from hazardsand the fact that the nation cannot seem to reduce themresult from shortsighted and narrow conceptions of the human relationship to the natural environment.

To redress those shortcomings, the nation must shift to a policy of "sustainable hazard mitigation." This concept links wise management of natural resources with local economic and social resiliency, viewing hazard mitigation as an integral part of a much larger context. Many aspects of this strategy were implicit in the recommendations formulated by White and Haas a quarter-century ago.

But to head off the continued rise in tolls from disasters, those principles must become more explicit.

This book reflects the efforts of over a hundred experts who have worked and debated since 1994 to take stock of Americans' relationship to hazards past, present, andmost importantlyfuture. Those contri butions have been used to outline a comprehensive approach to enhancing society's ability to reduce the costs of disaster.

The Roots of the Problem

Many disaster lossesrather than stemming from unexpected eventsare the predictable result of interactions among three major systems: the physical environment, which includes hazardous events; the social and demographic characteristics of the communities that experience them; and the buildings, roads, bridges, and other components of the constructed environment. Growing losses result partly from the fact that the nation's capital stock is expanding, but they also stem from the fact that all these systemsand their interactionsare becoming more complex with each passing year.

Three main influences are at work. First, the earth's physical systems are constantly changingwitness the current warming of the global climate. Scientists expect a warming climate to produce more dramatic meteorological events such as storms, floods, drought, and extreme temperatures. Second, recent and projected changes in the demographic composition and distribution of the U.S. population mean greater exposure to many hazards. The number of people residing in earthquake-prone regions and coastal counties subject to hurricanes, for example, is growing rapidly. Worsening inequality of wealth also makes many people more vulnerable to hazards and less able to recover from them. Third, the built environmentpublic utilities, transportation systems, communications, and homes and office buildingsis growing in density, making the potential losses from natural forces larger.

Settlement of hazardous areas has also destroyed local ecosystems that could have provided protection from natural perils. The draining of swamps in Florida and the bulldozing of steep hillsides for homes in California, for example, have disrupted natural runoff patterns and magnified flood hazards. And many mitigation efforts themselves degrade the environment and thus contribute to the next disaster. For example, levees built to provide flood protection can destroy riparian habitat and heighten downstream floods.

Another major problem has become clear over the past 20 years: some efforts to head off damages from natural hazards only postpone them. For example, communities below dams or behind levees may avoid losses from floods those structures were designed to prevent. But such communities often have more property to lose when those structures fail, because additional development occurred that counted on protection. Such a situation contributed to catastrophic damage from the 1993 floods in the Mississippi basin. And many of the nation's dams, bridges, and other structures are approaching the end of their designed life, revealing how little thought their backers and builders gave to events 50 years hence. Similarly, by providing advance warnings of severe storms, this country may well have encouraged more people to build in fragile coastal areas. Such development, in turn, makes the areas more vulnerable by destroying dunes and other protective natural features.

Fostering Local Sustainability

Sustainability means that a locality can tolerateand overcomedamage, diminished productivity, and reduced quality of life from an extreme event without significant outside assistance. To achieve sus-tainability, communities must take responsibility for choosing where and how development proceeds. Toward that end, each locality evaluates its environmental resources and hazards, chooses future losses that it is willing to bear, and ensures that development and other community actions and policies adhere to those goals.

Disaster Losses Are Growing

From 1975 to 1994, natural hazards killed over 24,000 people and injured some 100,000 in the United States and its territories. About one-quarter of the deaths and half the injuries resulted from events that society would label as disasters. The rest resulted from less dramatic but more frequent events such as lightning strikes, car crashes owing to fog, and localized landslides.

The United States has succeeded in saving lives and reducing injuries from some natural hazards such as hurricanes over the last two decades. However, casualties from floods-the nation's most frequent and injurious natural hazardhave failed to decline substantially. And deaths from lightning and tornadoes have remained constant. Meanwhile injuries and deaths from dust storms, extreme cold, wildfire, and tropical storms have grown.

The dollar losses associated with most types of natural hazards are rising. A conservative estimate of total dollar losses during the past two decades is $500 billion (in 1994 dollars). More than 80 percent of these costs stemmed from climatological events, while around 10 percent resulted from earthquakes and volcanoes. Only 17 percent were insured. Determining losses with a higher degree of accuracy is impossible because the United States has not established a systematic reporting method or a single repository for the data. Further, these numbers do not include indirect costs such as downtime for businesses, lost employment, environmental damage, or emotional effects on victims. Most of these losses result from events too small to qualify for federal assistance, and most are not insured, so victims must bear the costs.

Seven of the ten most costly disastersbased on dollar lossesin U.S. history occurred between 1989 and 1994. In fact, since 1989 the nation has frequently entered periods in which losses from catastrophic natural disasters averaged about $1 billion per week. The dramatic increase in disaster losses is expected to continue.

Many of the harshest recent disasters could have been far worse: had Hurricane Andrew been slower and wetter or torn through downtown Miami, for example, it would have wreaked devastation even more profound than the damage it did inflict. And the most catastrophic likely events, including a great earthquake in the Los Angeles area, have not yet occurred. Such a disaster would cause up to 5,000 deaths, 15,000 serious injuries, and $250 billion in direct economic losses.

Six objectives must simultaneously be reached to mitigate hazards in a sustainable way and stop the national trend toward increasing catastrophic losses from natural disasters.

  • Maintain and enhance environmental quality. Human activities to mitigate hazards should not reduce the carrying capacity of the ecosystem, for doing so increases losses from hazards in the longer term.

  • Maintain and enhance people's quality of life. A population's quality of life includes, among other factors, access to income, education, health care, housing, and employment, as well as protection from disaster. To become sustainable, local communities must consciously define the quality of life they want and select only those mitigation strategies that do not detract from any aspect of that vision.

  • Foster local resiliency and responsibility. Resiliency to disasters means a locale can withstand an extreme natural event with a tolerable level of losses. It takes mitigation actions consistent with achieving that level of protection.

  • Recognize that vibrant local economies are essential. Communities should take mitigation actions that foster a strong local economy rather than detract from one.

  • Ensure inter- and intra-generational equity. A sustainable community selects mitigation activities that reduce hazards across all ethnic, racial, and income groups, and between genders equally, now and in the future. The costs of today's advances are not shifted onto later generations or less powerful groups.

  • Adopt local consensus building. A sustainable community selects mitigation strategies that evolve from full participation among all public and private stakeholders. The participatory process itself may be as important as the outcome.

A long-term, comprehensive plan for averting disaster losses and encouraging sustainability offers a locality the opportunity to coordinate its goals and policies. A community can best forge such a plan by tapping businesses and residents as well as experts and government officials. And while actual planning and follow-through must occur at the local level, a great deal of impetus must come from above. Nothing short of strong leadership from state and federal governments will ensure that planning for sustainable hazard mitigation and development occurs.

Mitigation Tools

Over the past few decades an array of techniques and practices has evolved to reduce and cope with losses from hazards and disasters. These and other tools will be vital in pursuing sustainable hazard mitigation.

Who is at Risk

Research has shown that people are typically unaware of all the risks and choices they face. They plan only for the immediate future, overestimate their ability to cope when disaster strikes, and rely heavily on emergency relief.

Hazard researchers now also recognize that demographic differences play a large role in determining the risks people encounter, whether and how they prepare for disasters, and how they fare when disasters occur. For example, non-minorities and households with higher socioeconomic status fare better, while low-income households are at greater risk mainly because they live in lower-quality housing, and because disasters exacerbate poverty.

The need for mitigation and response efforts that acknowledge the demographic differences among the nation's citizens will become even more critical as the U.S. population becomes more diverse. Research is also needed to shed further light on how mitigation programs ranging from public education to disaster relief can be rendered equitably.

Land Use

Wise land-use planning that limits expansion into sensitive areas is essential to sustainable hazard mitigation. Indeed, land-use planning, hazard mitigation, and sustainable communities are concepts with a shared vision in which people and property are kept out of the way of hazards, the mitigative qualities of the natural environment are maintained, and development is resilient in the face of natural forces.

Unfortunately, no overarching guidance informs development in hazard-prone areas. Instead, a patchwork of innumerable federal, state, and local regulations creates a confusing picture and often reduces short-term losses while allowing the potential for catastrophic losses to grow. This scattershot approach, as well as the federal and state trend to cut risk and assume liability, have undermined the responsibility of local governments for using land-use management techniques to reduce exposure to hazards.


Since the first assessment was completed, significant improvements in short-term forecasts and warnings (hours to days ahead of a hazardous event) have dramatically reduced loss of life and injury in the United States. Yet many communities lag in their ability to provide citizens with effective warning messages. The nation needs to make local warning systems more uniform, develop a comprehensive model for how they work, and provide this information to local communities along with technical assistance. Better local management and decision making are now more critical than most future advances in technology.

It's also important to remember that short-term warning systems do not significantly limit damage to the built environment, nor do they mitigate economic disruption from disasters. Long-range forecasts that help define the risks to local communities years to decades ahead of potential hazards could assist local decisionmakers in designing their communities to endure them.

Engineering and building codes

The ability of the built environment to withstand the impacts of natural forces plays a direct role in determining the casualties and dollar costs of disasters. Disaster-resistant construction of buildings and infrastructure is therefore an essential component of local resiliency. Engineering codes, standards, and practices have been promulgated for natural hazards. Local governments have also traditionally enacted building codes. However, investigations after disasters have revealed shortcomings in construction techniques and code enforcement. Codes, standards, and practices for all hazards must be reevaluated in light of the goal of sustainable mitigation, and communities must improve adherence to them.


The public increasingly looks to insurance to compensate for losses from many types of risk-taking behavior. However, most property owners do not buy coverage against special perils, notably earthquakes, hurricanes, and floods. For example, nationwide only about 20 percent of the homes exposed to floods are insured for them. Many people assume that federal disaster assistance will function as a kind of hazard insurance, but such aid is almost always limited. And even when larger amounts are available, they are usually offered in the form of loans, not outright grants.

Insurance does help minimize some disruption by ensuring that people with coverage receive compensation for their losses as they begin to recover. The insurance industry could facilitate mitigation by providing information and education, helping to create model codes, offering financial incentives that encourage mitigation, and limiting the availability of insurance in high-hazard areas.

The industry already has problems providing insurance in areas subject to catastrophic losses because many insurers do not have the resources to pay for a worst-case event. Furthermore, the current regula tory system makes it difficult to aggregate adequate capital to cover low-frequency but high-consequence events.

New technology

Computer-mediated communication systems, geographic information systems (GIS), remote sensing, electronic decision-support systems, and risk-analysis techniques have developed substantially during the last two decades and show great promise for supporting sustainable hazard mitigation. For example, GIS models enable managers to consolidate information from a range of disciplines, including the natural and social sciences and engineering, and to formulate plans accordingly.

Remote sensing can be used to make land-use maps and show changes over time, feed information to GIS models, and gather information in the wake of disasters. Finally, decision-support systems can fill a gap in hazards management by analyzing information from core databases, including data on building inventories, infrastructure, demographics, and risk. The systems can then be used to ask "what-if" questions about future losses to inform today's decision making. Such systems are now constrained by the lack of comprehensive local data, but they will become more important as the process of evaluating and managing risk grows in complexity.

Essential Steps

The shift to a sustainable approach to hazard mitigation will require extraordinary actions. Here are several essential steps; note that many initial efforts are already under way.

Build local networks, capability, and consensus

Today hazard specialists, emergency planners, resource managers, community planners, and other local stakeholders seek to solve problems on their own. An approach is needed to forge local consensus on disaster resiliency and nurture it through the complex challenges of planning and implementation.

One potential approach is a "sustainable hazard mitigation network" in each of the nation's communities that would engage in collaborative problem solving. Each network would produce an integrated, comprehensive plan linking land-use, environmental, social, and economic goals. An effective plan would also identify hazards, estimate potential losses, and assess the region's environmental carrying capacity. The stakeholder network especially needs to determine the amount and kind of damage that those who experience disasters can bear. These plans would enable policymakers, businesses, and residents to understand the limitations of their region and work together to address them. Full consensus may never be reached, but the process is key because it can generate ideas and foster the sense of community required to mitigate hazards.

This kind of holistic approach will also situate mitigation in the context of other community goals that, historically, have worked against action to reduce hazards. Finally, the process will advance the idea that each locality controls the character of its disasters, forcing stakeholders to take responsibility for natural hazards and resources and realize that the decisions they make today will determine future losses.

Federal and state agencies could provide leadership in this process by sponsoring-through technical and financial supporta few prototype networks such as model communities or regional projects.

Establish a holistic government framework

To facilitate sustainable mitigation, all policies and programs related to hazards and sustainability should be integrated and consistent. One possible approach toward this goal is a conference or series of conferences that enable federal, state, county, and city officials to reexamine the statutory and regulatory foundations of hazard mitigation and preparedness, in light of the principles of sustainable mitigation. Potential changes include limiting the subsidization of risk, making better use of incentives, setting a federal policy for guiding land use, and fostering collaboration among agencies, nongovernmental organizations, and the private sector.

Emergency Preparedness and Recovery

Even if encouraged by more holistic state and federal policies, sustainable hazard mitigation will never eliminate the need for plans to address the destruction and human suffering imposed by disasters. In fact, one way to progress toward sustainable hazard mitigation is by creating policies for disaster preparedness, response, and recovery that support that goal.

A great deal of research has focused on pre-disaster planning and response since the 1975 assessment. Studies have found that pre-disaster planning can save lives and injuries, limit property damage, and minimize disruptions, enabling communities to recover more quickly.

Recovery was once viewed as a linear phenomenon, with discrete stages and end products. Today it is seen as a process that entails decision making and interaction among all stakeholdershouseholds, businesses, and the community at large. Research has also shown that recovery is most effective when community-based organizations assume principal responsibility, supplemented by outside technical and financial assistance. An even further shift--away from an exclusive focus on restoring damaged structures toward effective decision making at all levels--may be needed. Outside technical assistance can help strengthen local organizational and decision-making capacity.

Local leaders too often fail to take advantage of the recovery period to reshape their devastated communities to withstand future events. Most local disaster plans need to be extended not only to explicitly address recovery and reconstruction but to identify opportunities for rebuilding in safer ways and in safer places.

Fortunately, revisions to disaster legislation in the last several years have allowed a greater percentage of federal relief monies to fund mitigation programs. Pre-disaster planning for post-disaster recovery is vital to communities' ability to become disaster resilient.

Other efforts to foster a comprehensive government framework could include a joint congressional committee hearing, a congressional report, a conference by the American Planning Association to review experiences in sample communities, and a joint meeting of federal, state, and professional research organizations.

Conduct a nationwide hazard and risk assessment

Not enough is known about the changes in or interactions among the physical, social, and constructed systems that are reshaping the nation's hazardous future. A national risk assessment should meld information from those three systems so hazards can be estimated interactively and comprehensively, to support local efforts on sustainable mitigation.

Local planning will require multi-hazard, community-scale risk assessment maps that incorporate information ranging from global physical processes to local resources and buildings. This information is not now available, and will require federal investment in research on risk-analysis tools and dissemination to local governments.

Build national databases

The nation must collect, analyze, and store standardized data on losses from past and current disasters, thereby establishing a baseline for comparison with future losses. This database should include information on the types of losses, their locations, their specific causes, and the actual dollar amounts, taking into account problems of double-counting, comparisons with gross domestic product, and the distinction between regional and national impacts. A second database is needed to collate information on mitigation effortswhat they are, where they occur, and how much they costto provide a baseline for local cost-benefit analysis. These archives are fundamental to informed decision making and should be accessible to the public.

A central repository for hazard-related social science data is also lacking. This third central archive would speed development of standards for collecting and analyzing information on the social aspects of hazards and disasters.

A New Approach to Hazards

Researchers and practitioners in the hazards community need to shift their strategy to cope with the complex factors that contribute to disasters in today'sand especially tomorrow'sworld. Here are the main guidelines for improving our ability to mitigate hazards.

  • Adopt a global systems perspective. Rather than resulting from surprise environmental events, disasters arise from the interactions among the earth's physical systems, its human systems, and its built infrastructure. A broad view that encompasses all three of these dynamic systems and interactions among them can enable professionals to find better solutions.

  • Accept responsibility for hazards and disasters. Human beingsnot natureare the cause of disaster losses, which stem from choices about where and how human development will proceed. Nor is there a final solution to natural hazards, since technology cannot make the world safe from ALL the forces of nature.

  • Anticipate ambiguity and change. The view that hazards are relatively static has led to the false conclusion that any mitigation effort is desirable and willin some vague wayreduce the grand total of future losses. In reality, change can occur quickly and nonlinearly. Human adaptation to hazards must become as dynamic as the problems presented by hazards themselves.

  • Reject short-term thinking. Mitigation as frequently conceived is too short-sighted. In general, people have a cultural and economic predisposition to think primarily in the short term. Sustainable mitigation will require a longer-term view that takes into account the overall effect of mitigation efforts on this and future generations.

  • Account for social forces. Societal factors, such as how people view both hazards and mitigation efforts or how the free market operates, play a critical role in determining which steps are actually taken, which are overlooked, and thus the extent of future disaster losses. Because such social forces are now known to be much more powerful than disaster specialists previously thought, growing understanding of physical systems and improved technology cannot suffice. To effectively address natural hazards, mitigation must become a basic social value.

  • Embrace sustainable development principles. Disasters are more likely where unsustainable development occurs, and the converse is also true: disasters hinder movement toward sustainability because, for example, they degrade the environment and undercut the quality of life. Sustainable mitigation activities should strengthen a community's social, economic, and environmental resiliency, and vice versa.

Provide comprehensive education and training

Today hazard managers are being called upon to tackle problems they have never before confronted, such as understanding complex physical and social systems, conducting sophisticated cost-benefit analyses, and offering long-term solutions. Education in hazard mitigation and preparedness should therefore expand to include interdisciplinary and holistic degree programs. Members of the higher education community will have to invent university-based programs that move away from traditional disciplines toward interdisciplinary education that solves the real-world problems entailed in linking hazards and sustainability. This will require not only new degree programs but also changes in the way institutions of higher education reward faculty, who now are encouraged to do theoretical work.

Measure progress

Baselines for measuring sustainability should be established now so the nation can gauge future progress. Interim goals for mitigation and other aspects of managing hazards should be set, and progress in reaching those goals regularly evaluated. This effort will require determining how to apply criteria such as disaster resiliency, environmental quality, intra- and inter-generational equity, quality of life, and economic vitality to the plans and programs of local communities.

Also important is evaluating hazard-mitigation efforts already in place before taking further steps in the same direction. For example, the National Flood Insurance Program, which combines insurance, incentives, and land-use and building standards, has existed for 30 years, yet its effectiveness has never been thoroughly appraised.

Each disaster yields new knowledge relevant to hazard mitigation and disaster response and recovery, yet no entity collects this information systematically, synthesizes it into a coherent body of knowledge, and evaluates the nation's progress in putting knowledge into practice. Systematic post-disaster audits, called for in the 1975 assessment by White and Haas, are still needed.

Share knowledge internationally

The United States must share knowledge and technology related to sustainable hazard mitigation with other nations, and be willing to learn from those nations as well. Both here and abroad, disaster experts also need to collaborate with development experts to address the root causes of vulnerability to hazards, including overgrazing, deforestation, poverty, and unplanned development. Disaster reduction should be an inherent part of everyday development processes, and international development projects must consider vulnerability to disaster.

The Key Role of the Hazards Community

To support sustainable hazard mitigation, researchers and practitioners need to ask new questions as well as continue to investigate traditional topics. Important efforts will include interdisciplinary research and education, and the development of local hazard assessments, computer-generated decision-making aids, and holistic government policies.

Future work must also focus on techniques for enlisting public and governmental support for making sustainable hazard mitigation a fundamental social value. Members of the hazards community will play a critical role in initiating the urgently needed nationwide conversation on attaining that goal.

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