This alert expired on 30 August 2026 at 19:45 UTC. It is kept here as a record.
No stronger detection stands among the 5 recorded within 20 km of this point since 14 May 2026 — one other scored the same. The last comparable one was on 14 August 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 30 at 12:40PM MDT until August 30 at 1:45PM MDT by NWS Glasgow MT
How we know
Confirmed by 4 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 71 % 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 | 71% |
| Coordinates | 47.0712, -106.0550 |
| Nearest City | Williston (218 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-30T18:40:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Dawson, MT; Garfield, MT; McCone, MT; Prairie, MT |
| Headline | Severe Thunderstorm Warning issued August 30 at 12:40PM MDT until August 30 at 1:45PM MDT by NWS Glasgow MT |
| Expires | 2026-08-30T13:45:00-06:00 |
| SenderName | NWS Glasgow MT |
| HasExactCoords | true |
| Spc ReportType | wind |
| Spc Speed | 65 |
| Spc Location | 2 NW Rock Springs |
| Spc County | Rosebud |
| Spc State | MT |
| Spc Comments | Mesonet station MTHIL 1.6 NW Rock Springs (MT DOT). (BYZ) |
| Iem TypeSummary | G |
| Iem Magnitude | 62 |
| Iem Unit | MPH |
| Iem City | 10 SSW Cohagen |
| Iem County | Garfield |
| Iem State | MT |
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 Williston (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.