, .. r . .. ~ ...... 1 . ,.' Twenty Years Later ' , < . , , . ~ ," ':L '~, ", ~ ' What ,~We Have . ":"' learned' Since the ".,!.,.. 'f . Big thompson flood .... '.. .. ~ .. , ' . .. <o?; f . .- , : -: ..... >, '. , . Proceedings of a Meeting . Held in Fort Collins, Colorado , . July 13-15, 1996. • > • '. TWENTY YEARS LA TER WHAT WE HAVE LEARNED SINCE THE BIG THOMPSON FLOOD Eve Gruntfest Editor Proceedings of a Meeting Held in Fort Collins, Colorado July 13-15, 1996 Special Publication No. 33 Natural Hazards Research and Applications Information Center University of Colorado Boulder, Colorado The opinions contained in this volume are those of the authors and do not necessarily represent the views of the funding or sponsoring organiza­ tions. The use of trademarks or brand names.in these papers is not intended as an endorsement of any product. Published 1997. This volume is available from: The Natural Hazards Research and Applications Information Center Institute of Behavioral Science Campus Box 482 University of Colorado Boulder, CO 80309-0482 tel: (303) 492-6819 fax: (303) 492-2151 e-mail: [email protected] WWW: http://www .colorado. edu/hazards ii TABLE OF CONTENTS Table of Contents . .. iii Acknowledgments .............................. vii List of Abbreviations ............................ ix List of Participants . x INTRODUCTION AND OVERVIEW ................... 1 PART 1: FEDERAL PERSPECTIVE Barriers and Opportunities in Mitigation Richard W. Krimm ............................ 15 The Bureau of Reclamation and Dam Safety Howard Gunnarson ........................... 21 Flood Warning/Preparedness Programs of the Corps of Engineers Kenneth Zwickl .............................. 26 PART II: DAM SAFETY Olympus Dam Early Warning System David B. Fisher . 31 Dams, Defects, and Time Wayne J. Graham ............................ 40 1996 Willamette and Columbia River Flood Cynthia A. Henriksen .......................... 50 PART III: HUMAN DIMENSIONS OF DISASTER Emergency Communications: A Survey of the Century's Progress and Implications for Future Planning Bascombe J. Wilson ........................... 57 Coping Self-Efficacy Following Natural and Human-Caused Disasters Charles C. Benight . 65 Church World Service and Lessons Learned for Mitigation Kristina J. Peterson and Richard L. Krajeski ........... 75 Table of Contents PART IV: METEOROLOGICAL CAPABILITIES AND CLIMATOLOGICAL ISSUES National Weather Service Advanced Capabilities in Flash Flood Forecasting Lee W. Larson 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 83 Comparison of Deficiencies Associated with the Big Thompson Flash Flood Event and Recent Flood Events in the Eastern United States Solomon Go Summer 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 90 Climatology of Extreme Rain Events in the United States from Hourly Precipitation Observations Harold E. Brooks, David Jo Stensrud, and Daniel Vo Mitchell 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 103 The Flash Flood Forecaster Course at the National Weather Service Training Center: The Environmental Research Laboratories Component Harold Eo Brooks, Charles Ao Doswell III, Robert Ao Maddox, Dennis Ao Rodgers, and Barry Schwartz 0 0 0 0 0 0 0 0 0 0 0 0 0 111 PART V: WARNING SYSTEMS Caliente Creek ALERT Flood Warning System Audit Clark Farr and David C. Curtis 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 121 Evolution of Local Flood Warning Systems and Early Notification Procedures in Denver, Colorado Kevin Go Stewart 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 133 Putting Effective Flood Warning Systems in Place: The Process and Guidelines in Australia John Handmer and Chas Keys 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 141 PART VI: INTERNATIONAL EXPERIENCES Flash Floods in Mexico Mao Teresa Vazquez, Ramon Dominguez, Oscar Fuentes, and Jose Antonio Maza 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 153 Flooding and the Demise of the Moche Empire Kenneth Ro Wright and John Dracup 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 161 iv Table of Contents PART VII: PALEOHYDROLOGICAL METHODS Problems with Use of Statistical Probability as a Tool for Prediction of Extreme Events Gregory G. Hammer . .. 171 Bayesian Flood Frequency Analysis with Paleohydrologic Bounds for Late Holocene Paleofloods, Santa Ynez River, California Daniel R.H. O'Connell, Daniel R. Levish, and Dean A. Ostenaa ......................... 183 Paleohydrologic Bounds and the Frequency of Extreme Floods Daniel R. Levish, Dean A. Ostenaa, and Daniel R.H. O'Connell . .. 197 v vi ACKNOWLEDGMENTS For 20 years I have been fortunate to have worked with an extraordi­ narily dedicated group of people devoted to lessening the impacts of flash floods. The 1996 Symposium re-emphasized that the Big Thompson flood had shaped the work of a generation of flood hazard mitigation experts. In this respect, the work of Bob Kistner, John Swanson, Larry Mooney, Robert Jarrett, Larry Stern, Wayne Graham, John Henz, Larry Larson, Kevin Stewart, Jack Truby, Len Boulas, and Patricia Hagan deserves special mention. Many people at the Federal Emergency Management Agency (FEMA) worked to develop the symposium. They w~re particularly supportive on program ideas. John Swanson provided encouragement from the moment I mentioned the idea to him two years before the actual meeting. Mike Armstrong, Steve Olsen, Tony Mendes, Mary Ahlstrom, Karen Morman, Floyd Shoemaker, Norm Lizotte, and Jay Wilson worked tirelessly. Dick Krimrn from headquarters provided fine remarks at the opening session. Jim Knoy from EPA, and Erik Nilsson served on the steering committee and were very supportive. Fred Sibley and Bill Rakocy at the Colorado Office of Emergency Management helped throughout the planning process and particularly with the smooth operation of the audio visual equipment at the symposium. Tommy Greer, Ron Cattany, Jerry Smith, and Polly White also from OEM contributed significantly to the success of the Symposium. Marc Weber, Carol Foster, and Diana Buchanan from the University of Colo­ rado-Colorado Springs and Doug Leas of the University of Nebraska-Omaha were essential to the smooth mechanics of the meeting in Fort Collins. The 1986 Symposium had a wide variety of sponsors and significant funding. The 1996 Symposium, on the contrary, was funded by enthusiasm more than by dollars, meaning a great deal more work for volunteers. There was little money available for the brochure and for promoting the Sympo­ sium. The World Wide Web site for the Symposium was linked with the FEMA homesite, and many important participants learned of the meeting through the Web, bringing interest from all over the world in a way that traditional means might not. We even had two young newlyweds, the Raflo's, fit the Symposium into their planned Rocky Mountain honeymoon after they found our site on the Web. When some people asked why we needed another Symposium, Jerry Peterson of the U. S. Army Corps of Engineers encouraged planning for the Acknowledgments meeting by pointing out that the Corps could have been intensively involved with warning efforts at the 1986 Symposium. His comment revealed that meetings can make a difference! He also arranged funding for the publication of these Proceedings. Bob Jarrett and Tom Yorke from USGS also gener­ ously provided some financial support. Lori Allen of Gallileo International is a consummate professional emergency manager. She may have sensed a looming disaster as the date of the Symposium approached. She leaped in with extraordinary organizational skills and managed the arrangements for the vendors (who were excellent additions to the Symposium) and worked closely with the hotel many crucial hours. Her dedication was essential to the success of the Symposium. The Saturday field trip through the Big Thompson Canyon added many dimensions to the Symposium experience; 30 people took part. Expert guidance from Bob Kistner, Bob Jarrett, Larry Stern, and particularly from Sharlynn Wamsley, a canyon resident, enabled us to recreate the flood stories and observe their lingering effects. Mary Fran Myers was a constant source of encouragement and assistance. Sylvia Dane did an excellent job assembling and editing the papers. Gilbert F. White unfortunately was unable to attend the Symposium, but his spirit and unwavering support for flood hazard mitigation efforts were present everywhere during the Symposium. Participants from five countries and 38 U. S. states joined to make this symposium a success. At the closing session on July 12th, when the notion of the 30th anniversary symposium was raised, I offered my support to the idea and turned the responsibility over to the next generation of flash flood mitigation specialists, including Dianne Brien, Pamela Pate, John England, and Patricia Gavelda. I look forward to working with them in 2006. Eve Gruntfest Symposium Organizer University of Colorado Colorado Springs, CO viii LIST OF ABBREVIATIONS ALERT Automated Local Emergency in Real Time AWHPS Area Wide Hydrologic Prediction System ASDSO American Society for Dam Safety Officials ASOS Automated Surface Radar Observing System AWIPS Advanced Weather Interactive Processing System CFS Chronic Fatigue Syndrome CRP Critical Rainfall Probability CSE Coping Self-Efficacy CWA County Warning Area CWS Church World Service EBS Emergency Broadcast System EMWIN Emergency Managers Weather Information Network ERL Environmental Research Laboratory EWS Early Warning System E&SS Kern County Engineering and Survey Services Department FEMA Federal Emergency Management Agency FSL Forecast Systems Laboratory HPD Hourly Precipitation Data ICOLD International Commission on Large Dams IFLOWS Integrated Flood Observing and Warning System MAR Modernization and Associated Restructuring (National Weather Service) NCDC National Center for Climatic Data NOAA National Oceanic and Atmospheric Administration NSSL National Severe Storms Laboratory NWR NOAA Weather Radio NWS National Weather Service QPF Quantitative Prediction Forecast PAR Population at Risk PMF Probable Maximum Flood PMP Probable Maximum Prediction ix LIST OF PARTICIPANTS Raul Acuna Rachel Badger Arcus Data Security, Inc.