Right now
The most recent data we hold from NOAA arrived 4 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 1 June 2026 at 02:45 UTC. It is kept here as a record.
It is the 17th strongest of the 50 detections recorded within 20 km of this point since 17 May 2026. Another comparable one was recorded here earlier the same day. 6 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 31 at 8:42PM CDT until May 31 at 9:45PM CDT by NWS Sioux Falls SD
An estimated 171,544 people live within 50 km of this point.
Nearby, since 17 May 2026
- June 1, 2026 · score 67 · 12.1 km
How we know
Confirmed by 4 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 89 % 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 | 89% |
| Coordinates | 43.1334, -96.9532 |
| Nearest City | Sioux Falls (49 km) |
| Population Exposed | 171.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-01T01:42:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.dc90778d360ba48ed5231be034c88c6c |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Clay, SD; Lincoln, SD; Turner, SD; Yankton, SD; Lincoln, SD; Turner, SD |
| Headline | Severe Thunderstorm Warning issued May 31 at 8:42PM CDT until May 31 at 9:45PM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-31T21:45:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.dc90778d360ba48ed5231be034c88c6cb7863f57.001.1","noaa_urn:oid:2.49.0.1.840.0.1db6cd7ca4dda28a1d6b07b77408dfe3fd01ff05.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 1 |
| Iem Unit | Inch |
| Iem City | 4 SW Hurley |
| Iem County | Turner |
| Iem State | SD |
| Iem Wfo | FSD |
| MergedSources | [{"id":"iem_H_43.010_-97.110_1780276620000","source":"iem","severity":"low","severityValue":25,"timestamp":1780276620000,"latitude":43.01,"longitude":-97.11},{"id":"iem_H_43.270_-97.040_1780275240000","source":"iem","severity":"low","severityValue":25,"timestamp":1780275240000,"latitude":43.27,"longitude":-97.04},{"id":"iem_H_43.240_-97.150_1780273980000","source":"iem","severity":"low","severityValue":25,"timestamp":1780273980000,"latitude":43.24,"longitude":-97.15}] |
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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