This alert expired on 4 September 2026 at 21:45 UTC. It is kept here as a record.
It is the 17th strongest of the 37 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 5 July 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 4 at 4:10PM CDT until September 4 at 4:45PM CDT by NWS La Crosse WI
Nearby, since 16 March 2026
- July 5, 2026 · score 22 · 3.4 km
- September 4, 2026 · score 28 · 4.4 km
- September 4, 2026 · score 28 · 15.3 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 16 out of 100, at 66 % 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 | 66% |
| Coordinates | 43.0575, -91.3363 |
| Nearest City | La Crosse (83 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-04T21:10:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.39da744cf6b20696ed6970ee733f29c3be1fa29b.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Allamakee, IA; Clayton, IA |
| Headline | Severe Thunderstorm Warning issued September 4 at 4:10PM CDT until September 4 at 4:45PM CDT by NWS La Crosse WI |
| Expires | 2026-09-04T16:45:00-05:00 |
| SenderName | NWS La Crosse WI |
| HasExactCoords | true |
| Spc ReportType | wind |
| Spc Speed | UNK |
| Spc Location | 4 NNE Waukon |
| Spc County | Allamakee |
| Spc State | IA |
| Spc Comments | Report of several trees down across Allamakee County. Time and location estimated from radar. (ARX) |
| MergedSources | [{"id":"spc_wind_43.32_-91.44_60","source":"spc","severity":"medium","severityValue":45,"timestamp":1788550680000,"latitude":43.32,"longitude":-91.44}] |
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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 16/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.