J14.4 In search of the ideal lead time: a social perspective and empirical analysis of the correlation between tornado warning lead time and casualties

Wednesday, 26 January 2011: 11:15 AM
618-620 (Washington State Convention Center)
JoBeth L. Minniear, Iowa State University, Ames, IA

As technology continually becomes more advanced and more is learned about tornadogenesis, tornado warnings have become more accurate and can be issued earlier than ever before. While the average lead time is close to thirteen minutes, many lead times have been greater than twenty minutes and a couple have been over one hour in the past few years. Is this longer lead time better for our society? Does an earlier warning for a tornado translate to more saved lives and property? This study focuses on two main topics: past tornadic events and the public's opinion of tornado lead times.

The warned tornadic events within the last three years have been analyzed to find if there was any correlation between several parameters—such as the storm's intensity, time, and lead time—with the casualties caused by the storm. Numerous people across the United States participated in a survey about his or her preference involving tornado lead times, along with other information relating to a person's behavior during a tornado warning. The survey included questions about demographics, tornado experience, preferred lead times, preparedness, activities during a warning, and how warnings and information were received. The information was then analyzed to find any correlations among the data.

Although the months of June through September have a similar amount of tornadoes as November through February, June through September has a lesser amount of casualties per storm. It was also found that the higher the intensity of the storm, the higher the amount of casualties per storm. The survey results show the Eastern and Western regions prefer a longer lead time than the South and Central regions. Participants who have never been in a tornado warning and participants with no action plan prefer longer lead times than those who have been in warnings or seen tornadoes. A very slight decrease in casualties was found with longer lead times, but a majority of participants in the study believe there can be too much of a lead time. A longer time period would be helpful for this study, but data was difficult to come by for this study. Possibilities of future work in this topic include the same study with more participants from underrepresented states or regions or a more detailed analysis of past storms and their lead times.

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