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This talk was originally presented at the 24th annual meeting of the National Weather Association held at the Capri Crown Plaza Resort in Biloxi, MS from 15-22 October 1999 by Dan Miller, the lead author and forecaster at the National Weather Service Forecast Office in Norman, OK. Here is the original abstract submitted to the conference:

Highway Overpasses as Tornado Shelters:
Fallout from the 3 May 1999 Oklahoma/Kansas Violent Tornado Outbreak

Daniel J. Miller, NOAA/National Weather Service Forecast Office, Norman OK

Charles A. Doswell III, NOAA/National Severe Storms Laboratory, Norman OK

Harold E. Brooks, NOAA/National Severe Storms Laboratory, Norman OK

Gregory J. Stumpf, NOAA/National Severe Storms Laboratory, Norman OK

Erik N. Rasmussen, NOAA/National Severe Storms Laboratory, Boulder CO

Abstract

During the late afternoon and evening hours of 3 May 1999, tornadic supercell thunderstorms produced several long-tracked violent tornadoes that struck parts of central Oklahoma and southern Kansas. During the course of this event, many people sought shelter from approaching tornadoes under highway overpasses. Over the past 20 years, public perception that highway overpasses offer sound shelter from tornado winds has increased substantially, mainly due to the events of 10 April 1979 in Wichita Falls, TX and, especially, a video from 26 April 1991 in southern Kansas that gained widespread distribution. However, it appears that highway overpasses offer, at best, questionable shelter not only from tornadoes, but severe storms in general: three people in Oklahoma lost their lives while seeking shelter near or under overpass bridges. Evidence will be presented from several severe weather episodes throughout the country, as well, to demonstrate that highway overpasses are not acceptable storm shelter areas, for a variety of reasons. Proposed ways will be presented to communicate this information to the public, in order to counteract the perception of overpasses as potential severe storm sheltering locations.

In particular, two major points about this topic need to be kept in mind:

1. Public perception that highway overpasses offer acceptable tornado and severe storm sheltering locations has been of great concern to many in the meteorological and emergency management professions long before the events of 3 May 1999 in central Oklahoma. The events of 3 May 1999 were merely the final motivating factor in the development of this presentation. And
2. This topic is only a very small part of overall tornado preparedness and safety activities AND the reasons why overpasses are very poor sheltering areas are intricately interwoven with the current tornado and severe storm safety guidelines as set forth by the National Weather Service, the Federal Emergency Management Agency, the American Red Cross, and the American Meteorological Society.

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