Right now
The most recent data we hold from NOAA arrived 3 hours 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 16 May 2026 at 00:00 UTC. It is kept here as a record.
It is the 3rd strongest of the 24 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 16 March 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 15 at 6:08PM CDT until May 15 at 7:00PM CDT by NWS Sioux Falls SD
Nearby, since 16 March 2026
- May 18, 2026 · score 46 · 3.0 km
- September 6, 2026 · score 16 · 14.7 km
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.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
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 |
| Legacy data-support index | 0.59/1 |
| Coordinates | 42.2787, -95.3617 |
| Nearest City | Sioux City (89 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-05-15T23:08:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.80d2e79a8dcf7b3281077ac418d44fa3 |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-05-15T23:08:00.000Z.
First archived: 2026-05-15T23:09:45.519Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Cherokee, IA; O'Brien, IA; Plymouth, IA; Sioux, IA; Ida, IA; Woodbury, IA; Emmet, IA; Palo Alto, IA and 3 more areas |
| Headline | Severe Thunderstorm Warning issued May 15 at 6:08PM CDT until May 15 at 7:00PM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-15T19:00:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 6 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.80d2e79a8dcf7b3281077ac418d44fa3b096e791.001.1","noaa_urn:oid:2.49.0.1.840.0.b85dd6b3cd0c29d95e4b751c92c93a494395e63b.001.1","noaa_urn:oid:2.49.0.1.840.0.42c316caf4ec3166ee70a1db357792776156e5f1.001.1","noaa_urn:oid:2.49.0.1.840.0.e635f84314d872c549e8fb49dcaa8739845c09c6.001.1","noaa_urn:oid:2.49.0.1.840.0.061a2e3f60759d4b61b1a855992def010845dd2f.001.1","noaa_urn:oid:2.49.0.1.840.0.c075dc5b48f74630a447bd2c0b5300f5acbd61b5.001.1"] |
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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