This alert expired on 18 July 2026 at 01:30 UTC. It is kept here as a record.
It is the 8th strongest of the 63 detections recorded within 20 km of this point since 8 March 2026. The last comparable one was on 29 May 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 17 at 6:58PM MDT until July 17 at 7:30PM MDT by NWS Great Falls MT
An estimated 59,638 people live within 50 km of this point.
Nearby, since 8 March 2026
- September 3, 2026 · score 45 · 18.3 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 39 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) | 39 / 100 |
| Our confidence | 80% |
| Coordinates | 47.5283, -111.6075 |
| Nearest City | Great Falls (23 km) |
| Population Exposed | 59.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-18T00:58:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.34b5160736e418247249b9a4154500f4b4657045.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Cascade, MT; Chouteau, MT; Teton, MT |
| Headline | Severe Thunderstorm Warning issued July 17 at 6:58PM MDT until July 17 at 7:30PM MDT by NWS Great Falls MT |
| Expires | 2026-07-17T19:30:00-06:00 |
| SenderName | NWS Great Falls MT |
| HasExactCoords | true |
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 near Great Falls?
Calamity.live data shows a weather event with CalamityScore 39/100, near Great Falls (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.