Right now
The most recent data we hold from NOAA arrived this minute, and this point is in it.
4 other detections within 20 km in the last 24 hours, the nearest 6 km from here.
This alert expired on 12 September 2026 at 03:15 UTC. It is kept here as a record.
It is the 15th strongest of the 43 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 4 September 2026. 13 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 11 at 9:24PM CDT until September 11 at 10:15PM CDT by NWS Sioux Falls SD
An estimated 82,821 people live within 50 km of this point.
Nearby, since 16 March 2026
- May 17, 2026 · score 39 · 8.6 km
- September 12, 2026 · score 32 · 17.6 km
- September 4, 2026 · score 32 · 19.6 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 32 out of 100, at 82 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 32 / 100 |
| Our confidence | 82% |
| Coordinates | 42.7600, -96.5545 |
| Nearest City | Sioux City (32 km) |
| Population Exposed | 82.8K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-12T02:24:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.a3d2d4fbcede5d0eebd9a9687425cbf442c91667.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Plymouth, IA; Sioux, IA; Dixon, NE; Clay, SD; Union, SD |
| Headline | Severe Thunderstorm Warning issued September 11 at 9:24PM CDT until September 11 at 10:15PM CDT by NWS Sioux Falls SD |
| Expires | 2026-09-11T22:15:00-05:00 |
| 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 8 March 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.
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