This alert expired on 25 May 2026 at 07:00 UTC. It is kept here as a record.
It is the 3rd strongest of the 39 detections recorded within 20 km of this point since 13 April 2026. Another comparable one was recorded here earlier the same day. 9 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 25 at 1:51AM CDT until May 25 at 2:00AM CDT by NWS Sioux Falls SD
Nearby, since 13 April 2026
- July 26, 2026 · score 22 · 11.4 km
- August 9, 2026 · score 22 · 21.5 km
- August 29, 2026 · score 22 · 23.2 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 out of 100, at 60 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 22 / 100 |
| Our confidence | 60% |
| Coordinates | 43.1540, -95.5420 |
| Nearest City | Sioux City (101 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-25T06:51:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | O'Brien, IA |
| Headline | Severe Thunderstorm Warning issued May 25 at 1:51AM CDT until May 25 at 2:00AM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-25T02:00:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Calamity.live data shows a weather event with CalamityScore 22/100, near Sioux City (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.