Preparing for Danger: On the Impact of Tornado Watches on Tornado Casualties
March 2014 (VOL. 32, NO. 1)
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We explore the impact of tornado watches on tornado casualties. The time needed to take
shelter for a tornado can be as little as a few minutes, but because warning lead times
averaged less than 15 minutes in 2004, a watch could alert residents to be ready to
receive and respond to a later warning. We find that casualties per tornado are greater
for tornadoes occurring within a tornado watch, although this difference vanishes when
controlling for tornado, warning, and path characteristics in a regression analysis. We
find no evidence that watches reduce casualties, either directly or by increasing the
effectiveness of tornado warnings. Tornadoes occurring within watches are more often
warned for and warnings reduce casualties, so watches do contribute to lives saved
through the warning process.