Severe weather in United States
This alert expired on 17 July 2026 at 22:00 UTC. It is kept here as a record.
No stronger detection stands among the 31 recorded within 20 km of this point since 8 March 2026 — 3 others scored the same. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 17 at 3:36PM MDT until July 17 at 4:00PM MDT by NWS Great Falls MT
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 out of 100, at 60 % 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 | 60% |
| Coordinates | 47.5620, -112.4170 |
| Nearest City | Great Falls (84 km) |
| Impact Tier | minor |
| Timestamp | 2026-07-17T21:36:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.26f7d93b190c19e6950fac5e80f66671 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Cascade, MT; Lewis and Clark, MT; Teton, MT; Lewis and Clark, MT; Teton, MT |
| Headline | Severe Thunderstorm Warning issued July 17 at 3:36PM MDT until July 17 at 4:00PM MDT by NWS Great Falls MT |
| Expires | 2026-07-17T16:00:00-06:00 |
| SenderName | NWS Great Falls MT |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.26f7d93b190c19e6950fac5e80f66671438b9a9c.001.1","noaa_urn:oid:2.49.0.1.840.0.54560f6b1b5a7abaef564a30144d84ae0079dfaf.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 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.
Want to know when something happens near Great Falls?
Calamity.live data shows a weather event with CalamityScore 22/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 187 scientific monitoring sources.