This alert expired on 29 August 2026 at 22:45 UTC. It is kept here as a record.
No stronger detection stands among the 16 recorded within 20 km of this point since 21 May 2026 — 14 others scored the same. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 29 at 4:26PM MDT until August 29 at 4:45PM MDT by NWS Cheyenne WY
Nearby, since 21 May 2026
- August 8, 2026 · score 22 · 21.3 km
- May 21, 2026 · score 22 · 25.0 km
How we know
Confirmed by 4 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 70 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 22 / 100 |
| Our confidence | 70% |
| Coordinates | 42.6068, -103.5940 |
| Nearest City | Rapid City (166 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-29T22:26:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Dawes, NE; Sioux, NE; Fall River, SD; Scotts Bluff, NE; Sioux, NE |
| Headline | Severe Thunderstorm Warning issued August 29 at 4:26PM MDT until August 29 at 4:45PM MDT by NWS Cheyenne WY |
| Expires | 2026-08-29T16:45:00-06:00 |
| SenderName | NWS Cheyenne WY |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.28f3b266e1ad8108ed6b920f8e7883b23048c97e.001.1","noaa_urn:oid:2.49.0.1.840.0.7c29abfad5f1200ed7969b3669ddac371b67f046.001.1","noaa_urn:oid:2.49.0.1.840.0.aae62c33f3a5191803b12461a57210aff26b5cf5.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 59 |
| Iem Unit | MPH |
| Iem City | 8 NW Harrison |
| Iem County | Sioux |
| Iem State | NE |
| Iem Wfo | CYS |
| Iem Remark | Davis weatherlink sensor. |
| MergedSources | [{"id":"iem_G_42.790_-104.310_1788039600000","source":"iem","severity":"low","severityValue":25,"timestamp":1788039600000,"latitude":42.79,"longitude":-104.31},{"id":"iem_G_42.700_-104.220_1788040500000","source":"iem","severity":"low","severityValue":25,"timestamp":1788040500000,"latitude":42.7,"longitude":-104.22},{"id":"iem_G_42.780_-103.990_1788040800000","source":"iem","severity":"low","severityValue":25,"timestamp":1788040800000,"latitude":42.78,"longitude":-103.99}] |
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 10 February 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.
Calamity.live data shows a weather event with CalamityScore 22/100, near Rapid City (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.