Severe Thunderstorm Warnings in the United States
713,327 severe thunderstorm warnings since 1986. Each alert counts once, however many counties it covered. The archive of severe thunderstorm warnings reaches back to 1986.
Severe Thunderstorm Warnings by state
Each state shaded by its count. Tap a state for its own archive.
- Severe Thunderstorm Warnings
- 713,327
- Busiest year
- 200826,562 severe thunderstorm warnings
- Average year
- 17,398over 41 years on file
- Busiest day
- July 22, 2008528 severe thunderstorm warnings
Over time
By year
Before October 2007 these were issued for whole counties, and a storm crossing three counties was often three warnings; since then one polygon follows the storm. The count changed with the practice, not only with the weather.
By month of the year
By state
Every state and territory, with the alerts that covered any part of it. Each state’s page lists every one of them.
- Texas78,397
- Kansas42,167
- Oklahoma39,130
- Nebraska32,659
- Missouri29,255
- Arkansas27,113
- Georgia26,459
- Mississippi26,295
- North Carolina24,098
- Alabama23,196
- Illinois21,583
- South Dakota21,457
- Tennessee21,267
- Florida20,842
- Iowa20,090
- Ohio20,014
- Kentucky19,591
- Colorado19,373
- Virginia18,557
- Pennsylvania18,375
- Minnesota17,598
- Louisiana17,589
- Indiana16,202
- South Carolina15,849
- New York14,293
- Wisconsin13,277
- Michigan12,586
- Montana12,124
- North Dakota11,949
- New Mexico11,755
- Arizona10,864
- West Virginia9,310
- Wyoming7,895
- Maryland7,176
- New Jersey4,650
- California3,575
- Maine3,353
- Massachusetts3,322
- Idaho3,194
- Utah2,890
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Rebuilt daily.