This alert expired on 29 August 2026 at 10:45 UTC. It is kept here as a record.
No stronger detection stands among the 13 recorded within 20 km of this point since 13 April 2026 — 2 others scored the same. The last comparable one was on 4 August 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 29 at 5:08AM CDT until August 29 at 5:45AM CDT by NWS Sioux Falls SD
Nearby, since 13 April 2026
- May 25, 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 62 % 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 | 62% |
| Coordinates | 42.9860, -95.7120 |
| Nearest City | Sioux City (78 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-29T10:08:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | O'Brien, IA; Sioux, IA |
| Headline | Severe Thunderstorm Warning issued August 29 at 5:08AM CDT until August 29 at 5:45AM CDT by NWS Sioux Falls SD |
| Expires | 2026-08-29T05:45:00-05:00 |
| 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.