This analysis reviewed more than 20 years of reports from the National Weather Service Storm Events Database. It analyzed reports of severe weather that caused deaths, injuries and/or $1 million or more in property or crop damage from January 1, 1998 to May 2019. All of the data are weather service estimates and do not reflect the final tallies of deaths, injuries and property damage recorded by other sources in the weeks and months following severe weather events. Comparing the data from one decade to another does not represent a trend in weather events, given the relatively short span of years.

The total number of deaths provided by the National Weather Service appeared to represent undercounts, when InsideClimate News compared the data to other sources. Similarly, estimates for damages in the database were generally preliminary and smaller than those available from other sources for some of the largest storms.

The weather service meteorologists who compile the Storm Events Database read news accounts, review autopsy reports, question tornado spotters, deputy sheriffs and consult other sources to try to determine how many people were killed or injured, either directly or indirectly by different types of dangerous weather, from flash floods to forest fires and from heat waves to blizzards. Each year, they log tens of thousands of entries into the database. Since 1996, that database has been standardized and improved by modern weather prediction tools as weather satellite and radar systems.

Extreme cold/snowstorms, wildfires, flooding and tornadoes all caused more reported fatalities from 2009-mid-2019 than they did the decade before, the analysis showed. Those specific types of severe weather – along with intense heat and hurricanes– remained the biggest killers over both decades.

Nevada was first among the top dozen states for the highest percentage increase in deaths related to severe weather. The state recorded 508 fatalities, an increase of 820 percent over the prior decade. Almost 90 percent of the deaths were related to heat. Nevada was followed by South Dakota (47/260 percent), New Mexico (90/210 percent), Alabama (397/200 percent), Montana (63/170 percent), Kentucky (166/160 percent), Wisconsin (237/130 percent), Idaho (53/96 percent), West Virginia (64/94 percent), Connecticut (27/93 percent), Arkansas (188/83 percent), and Nebraska (59/74 percent).

Texas recorded the highest numbers of severe weather-related deaths in the last decade (680), followed by Nevada (508), California (431), Florida (424), Alabama (397), Missouri (371), Illinois (353), North Carolina (256), Pennsylvania (251), Wisconsin (237) and New York (226).

Analysis: Lise Olsen
Graphics: Daniel Lathrop
Editing: Vernon Loeb