Right now
The most recent data we hold from NOAA arrived 4 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 1 June 2026 at 05:00 UTC. It is kept here as a record.
No stronger detection stands among the 18 recorded within 20 km of this point since 15 May 2026 — 9 others scored the same. The last comparable one was on 22 May 2026. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 31 at 11:08PM CDT until June 1 at 12:00AM CDT by NWS Sioux Falls SD
An estimated 82,821 people live within 50 km of this point.
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 39 out of 100, at 79 % 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) | 39 / 100 |
| Our confidence | 79% |
| Coordinates | 42.1950, -96.2070 |
| Nearest City | Sioux City (37 km) |
| Population Exposed | 82.8K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-01T04:08:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.fb2d98759222822be79405367d64e207 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Plymouth, IA; Woodbury, IA; Union, SD; Harrison, IA; Monona, IA; Burt, NE |
| Headline | Severe Thunderstorm Warning issued May 31 at 11:08PM CDT until June 1 at 12:00AM CDT by NWS Sioux Falls SD |
| Expires | 2026-06-01T00:00:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.fb2d98759222822be79405367d64e207119cc6fc.001.1","noaa_urn:oid:2.49.0.1.840.0.6e71b96649ec800211a019eb85697e2ae676e91a.001.1"] |
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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