Tornado Deaths: Limits of Current Technology

An earlier draft of this article first published as Tornado Deaths and the Limits of Tornado-Related Technologies onTechnorati.

Deaths in the southeastern United States related to the April 27, 2011 tornadoes prompt an examination of tornado safety.  A key question is whether modern tornado detection and warning technology significant reduces risk of tornado-related death.

Storm and tornado tracking technology has exploded over the last 30 years.  Doppler radar technology continues to improve and national and regional news channels trumpet their own systems with names such as SkyTraK DopplerMax, First Alert Mega Doppler Radar and Doppler 9000 HD.  Local news stations in the the midwestern  and southern U.S. regions frequently break into regular programming to alert viewers to potential dangerous storms and tornado watches.

In 1982, The Weather Channel started broadcasting in the United States.  This 24 hour channel monitors severe weather across the U.S. providing access to instant weather information.

But what has been the effect of these tornado technologies in the trends for tornado-related deaths?  The trends to do not appear to support these technologies in their ability to reduce tornado-related death.  Below is a plot of the yearly number of tornado-related deaths in the U.S. between 1950 and 2011 (year-to-date) from data published by the U.S. National Oceanic and Atmospheric Administration. 

Tornado-related deaths have dropped dramatically in the United States but the biggest declines occurred between 1925 and 1980.  Between 1875 and 1925, the U.S. averaged nearly two deaths per million residents.  Since 1980, the U.S. death rate has averaged around .2 deaths per million people.  This is around a 90 per cent decrease and a significant advance in public health safety.

The problem for tornado technology advocates is the trend in tornado-related deaths between 1980 and 2011.  The over 300 deaths in the recent southeastern U.S. tornado make 2011 already one of the top three years for tornado deaths in the U.S. since 1950.  The number of deaths so far in 2011 is topped by only by 1953 with 519 deaths and 1974 with 366 tornado-related deaths .  Yearly death rates vary significantly and should be corrected for total population to compare trends.  Taking a look at the rates of tornado-related deaths per million population finds the following results in the last six decades:

Decade      Total Deaths           Deaths/Million

1950s        1419                                  8.6

1960s          942                                 4.9

1970s          998                                 4.7

1980s          522                                 2.2

1990s          579                                 2.2

2000s          556                                 1.9
2010s          420

The decline in the 2000s to 1.9 deaths/million/decade is not statistically different than the rate for the decade of the 1980s or the rate for the 1990s decades.  The 300 deaths in the southeastern U.S. in the recent U.S. tornado is about the number that could be expected over a six year span in the U.S.  The likelihood that the tornado deaths in the 2010s will show a statistically significant decline seem small.


There is some data supporting regional tornado death decreases in the area surrounding new radar installations  Additionally, there is some support for increased numbers of residents and mobile homes in the southeastern U.S. potentially contributing to the plateau in number of tornado deaths in the U.S. Nevertheless, it's hard to look at the raw data and feel like tornado detection technology has dramatically reduced the risk of tornado death.

Technology has contributed to improvement in many areas of life.  Tornado-related deaths in the U.S. have dropped significantly in the U.S.  The timing of this decline suggests factors such as improved building safety may have contributed to this public health improvement.

However, the data do no support modern tornado detection and warning technology as  major factors in decreasing tornado-related deaths.   Without significant new technological advances, it appears a limit has been reached in reducing tornado-related deaths in the U.S.


The figure in this post is created by the author from public domain data.

Ashley, W. (2007). Spatial and Temporal Analysis of Tornado Fatalities in the United States: 1880–2005 Weather and Forecasting, 22 (6), 1214-1228 DOI: 10.1175/2007WAF2007004.1

Simmons, K., & Sutter, D. (2005). WSR-88D Radar, Tornado Warnings, and Tornado Casualties Weather and Forecasting, 20 (3), 301-310 DOI: 10.1175/WAF857.1


Brooks, Harold E (2002). Deaths in the 3 May 1999 Oklahoma City Tornado from a Historical Perspective Weather and Forecasting


The Science of Tornadoes--3 minute video from the History Channel