Alert archive / Severe Thunderstorm Warnings / 2021
Severe Thunderstorm Warnings in the United States, September 2021
828 severe thunderstorm warnings in September 2021. 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
- 828
- Busiest day
- September 7, 2021107 severe thunderstorm warnings
Over time
By day
Days in UTC, the clock the archive keeps.
By state
Every state and territory, with the alerts that covered any part of it. Each state’s page lists every one of them.
- Texas1,995
- Kansas887
- Pennsylvania803
- Oklahoma761
- Virginia683
- Nebraska649
- New York576
- Missouri569
- Arizona561
- Colorado556
- New Mexico499
- Mississippi497
- Arkansas497
- Alabama489
- South Dakota475
- Florida456
- Tennessee431
- Michigan427
- North Carolina425
- Illinois423
- Georgia409
- Iowa366
- Maryland360
- Louisiana359
- Wisconsin351
- Ohio350
- Minnesota329
- West Virginia302
- Kentucky292
- Indiana290
- North Dakota254
- New Jersey237
- South Carolina231
- Montana212
- Massachusetts151
- Wyoming145
- Utah121
- Connecticut91
- Maine81
- Nevada69
Nearby
Alerts in force nowThe tornado archiveThe radar archive20202022
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.