This alert expired on 20 June 2026 at 01:45 UTC. It is kept here as a record.
It is the 8th strongest of the 46 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 19 at 8:26PM CDT until June 19 at 8:45PM CDT by NWS La Crosse WI
An estimated 148,338 people live within 50 km of this point.
Nearby, since 15 March 2026
- June 20, 2026 · score 43 · 10.3 km
- June 10, 2026 · score 37 · 14.8 km
How we know
Confirmed by 8 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 91 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 43 / 100 |
| Our confidence | 91% |
| Coordinates | 44.1177, -91.2600 |
| Nearest City | Onalaska (26 km) |
| Population Exposed | 148.3K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-20T01:26:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.dc6ae145cdf26b567512123293369115776f3823.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Trempealeau, WI |
| Headline | Severe Thunderstorm Warning issued June 19 at 8:26PM CDT until June 19 at 8:45PM CDT by NWS La Crosse WI |
| Expires | 2026-06-19T20:45:00-05:00 |
| SenderName | NWS La Crosse WI |
| HasExactCoords | true |
| Iem TypeSummary | D |
| Iem City | Osseo |
| Iem County | Trempealeau |
| Iem State | WI |
| Iem Wfo | ARX |
| Iem Remark | Power poles and trees downed in Osseo. |
| MergedSources | [{"id":"iem_H_44.760_-91.280_1781910540000","source":"iem","severity":"low","severityValue":25,"timestamp":1781910540000,"latitude":44.76,"longitude":-91.28},{"id":"iem_C_44.610_-91.190_1781913180000","source":"iem","severity":"low","severityValue":25,"timestamp":1781913180000,"latitude":44.61,"longitude":-91.19},{"id":"iem_D_44.290_-91.720_1781917020000","source":"iem","severity":"low","severityValue":25,"timestamp":1781917020000,"latitude":44.29,"longitude":-91.72},{"id":"iem_H_44.580_-91.220_1781912700000","source":"iem","severity":"low","severityValue":25,"timestamp":1781912700000,"latitude":44.58,"longitude":-91.22},{"id":"iem_H_44.760_-91.460_1781909640000","source":"iem","severity":"low","severityValue":25,"timestamp":1781909640000,"latitude":44.76,"longitude":-91.46},{"id":"iem_H_44.590_-91.170_1781912820000","source":"iem","severity":"low","severityValue":25,"timestamp":1781912820000,"latitude":44.59,"longitude":-91.17},{"id":"iem_D_44.580_-91.230_1781913000000","source":"iem","severity":"low","severityValue":25,"timestamp":1781913000000,"latitude":44.58,"longitude":-91.23}] |
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 near Onalaska?
Calamity.live data shows a weather event with CalamityScore 43/100, near Onalaska (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.