Right now
The most recent data we hold from NOAA arrived 5 minutes ago, and this point is in it.
One other detection within 20 km in the last 24 hours, 1 km from here.
This alert expired on 12 September 2026 at 04:15 UTC. It is kept here as a record.
It is the 19th strongest of the 37 detections recorded within 20 km of this point since 23 April 2026. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 11 at 10:51PM CDT until September 11 at 11:15PM CDT by NWS Sioux Falls SD
Nearby, since 23 April 2026
- July 2, 2026 · score 46 · 2.4 km
- July 8, 2026 · score 39 · 7.1 km
- May 22, 2026 · score 46 · 10.4 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 16 out of 100, at 67 % 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) | 16 / 100 |
| Our confidence | 67% |
| Coordinates | 42.4067, -95.7417 |
| Nearest City | Sioux City (55 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-12T03:51:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.79bd52f4b06adf88275fd0198bc4c458a743dbf8.002.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Ida, IA; Woodbury, IA |
| Headline | Severe Thunderstorm Warning issued September 11 at 10:51PM CDT until September 11 at 11:15PM CDT by NWS Sioux Falls SD |
| Expires | 2026-09-11T23:15:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| Spc ReportType | wind |
| Spc Speed | UNK |
| Spc Location | 1 ENE Le Mars |
| Spc County | Plymouth |
| Spc State | IA |
| Spc Comments | Report via social media of large tree down blocking road in Le Mars. (FSD) |
| MergedSources | [{"id":"spc_wind_42.79_-96.15_40","source":"spc","severity":"medium","severityValue":45,"timestamp":1789182000000,"latitude":42.79,"longitude":-96.15}] |
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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