Right now
The most recent data we hold from NOAA arrived 20 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 04:45 UTC. It is kept here as a record.
It is the 7th strongest of the 15 detections recorded within 20 km of this point since 16 March 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 May 31 at 11:38PM CDT until May 31 at 11:45PM CDT by NWS Omaha/Valley NE
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 out of 100, at 60 % 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) | 22 / 100 |
| Our confidence | 60% |
| Coordinates | 42.0539, -95.9728 |
| Nearest City | Sioux City (61 km) |
| Impact Tier | minor |
| Timestamp | 2026-06-01T04:38:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.2acc470d0ff067a6494ea6a0e5e0631f |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Harrison, IA; Monona, IA; Harrison, IA; Shelby, IA; Plymouth, IA; Woodbury, IA |
| Headline | Severe Thunderstorm Warning issued May 31 at 11:38PM CDT until May 31 at 11:45PM CDT by NWS Omaha/Valley NE |
| Expires | 2026-05-31T23:45:00-05:00 |
| SenderName | NWS Omaha/Valley NE |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.2acc470d0ff067a6494ea6a0e5e0631fa325f0c3.001.1","noaa_urn:oid:2.49.0.1.840.0.123ba9ea2cf9c4a69e8efa415ae166e99b729776.001.1","noaa_urn:oid:2.49.0.1.840.0.825f9e5a308cbb13d143ae3dac41e67f4272732d.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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