This alert expired on 12 August 2026 at 10:15 UTC. It is kept here as a record.
It is the strongest of the 20 detections recorded within 20 km of this point since 15 March 2026. The last comparable one was on 8 August 2026. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 12 at 4:16AM CDT until August 12 at 5:15AM CDT by NWS Sioux Falls SD
An estimated 24,366 people live within 50 km of this point.
Nearby, since 15 March 2026
- August 12, 2026 · score 32 · 14.1 km
- September 4, 2026 · score 28 · 15.7 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 34 out of 100, at 80 % 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) | 34 / 100 |
| Our confidence | 80% |
| Coordinates | 42.1356, -96.9030 |
| Nearest City | Norfolk (44 km) |
| Population Exposed | 24.4K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-12T09:16:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.e706b3015ccba89d5b9b92182e32e708 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Plymouth, IA; Woodbury, IA; Dakota, NE; Dixon, NE; Union, SD; Cedar, NE; Pierce, NE; Thurston, NE; Wayne, NE; Butler, NE; Colfax, NE; Cuming, NE; Dodge, NE; Madison, NE; Pierce, NE; Platte, NE; Saunders, NE; Stanton, NE; Thurston, NE; Wayne, NE |
| Headline | Severe Thunderstorm Warning issued August 12 at 4:16AM CDT until August 12 at 5:15AM CDT by NWS Sioux Falls SD |
| Expires | 2026-08-12T05:15:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.e706b3015ccba89d5b9b92182e32e70861aaf381.001.1","noaa_urn:oid:2.49.0.1.840.0.ad318c6e849e0bcd8d7beab05d155795e20404dc.001.1","noaa_urn:oid:2.49.0.1.840.0.28796bcec9f5f908808f3a3de56793f04cbfb613.001.1"] |
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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 34/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.