Right now
The most recent data we hold from NOAA arrived 3 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
4 other detections within 20 km in the last 24 hours, the nearest 12 km from here.
This alert expired on 6 September 2026 at 00:45 UTC. It is kept here as a record.
It is the strongest of the 40 detections recorded within 20 km of this point since 5 May 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Flash Flood Warning issued September 5 at 3:44PM MDT until September 5 at 6:45PM MDT by NWS Cheyenne WY
Nearby, since 5 May 2026
- July 10, 2026 · score 22 · 10.2 km
- July 28, 2026 · score 22 · 17.1 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 28 out of 100, at 65 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | High |
| Calamity Score (ours) | 28 / 100 |
| Our confidence | 65% |
| Coordinates | 42.3140, -102.9410 |
| Nearest City | Rapid City (198 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-05T21:44:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.876998c3c1746d9e2b963562dc9a436a12cef8b6.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Box Butte, NE; Dawes, NE |
| Headline | Flash Flood Warning issued September 5 at 3:44PM MDT until September 5 at 6:45PM MDT by NWS Cheyenne WY |
| Expires | 2026-09-05T18:45:00-06:00 |
| SenderName | NWS Cheyenne WY |
| HasExactCoords | true |
| Spc ReportType | hail |
| Spc Speed | 200 |
| Spc Location | 4 SSW Alliance |
| Spc County | Box Butte |
| Spc State | NE |
| Spc Comments | Trained Spotter reported 2 inch hail 4 miles SSW of Alliance. (CYS) |
| MergedSources | [{"id":"spc_hail_42.10_-102.99_146","source":"spc","severity":"high","severityValue":65,"timestamp":1788645360000,"latitude":42.1,"longitude":-102.99},{"id":"spc_hail_42.10_-102.97_147","source":"spc","severity":"high","severityValue":65,"timestamp":1788645660000,"latitude":42.1,"longitude":-102.97},{"id":"spc_hail_42.13_-102.96_148","source":"spc","severity":"high","severityValue":65,"timestamp":1788645900000,"latitude":42.13,"longitude":-102.96},{"id":"spc_hail_42.05_-102.90_149","source":"spc","severity":"high","severityValue":65,"timestamp":1788647400000,"latitude":42.05,"longitude":-102.9}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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 28/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.