This alert expired on 14 May 2026 at 04:00 UTC. It is kept here as a record.
No stronger detection stands among the 73 recorded within 20 km of this point since 17 March 2026 — 66 others scored the same. Another comparable one was recorded here earlier the same day. 8 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Watch issued May 13 at 8:52PM MDT until May 13 at 9:00PM MDT by NWS Great Falls MT
Nearby, since 17 March 2026
- August 30, 2026 · score 22 · 0.0 km
- July 26, 2026 · score 22 · 0.0 km
- July 25, 2026 · score 22 · 0.0 km
How we know
Confirmed by 6 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.
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) | 22 / 100 |
| Our confidence | 71% |
| Coordinates | 46.8000, -110.4000 |
| Nearest City | Great Falls (103 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-14T02:52:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Watch_noaa_urn:oid:2.49.0.1.840.0.376de6773b9edb8b92068270d0c7ecac |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Watch |
| Urgency | Future |
| Certainty | Possible |
| AreaDesc | Beaverhead, MT; Blaine, MT; Broadwater, MT; Cascade, MT; Chouteau, MT; Fergus, MT; Gallatin, MT; Hill, MT; Jefferson, MT; Judith Basin, MT; Lewis and Clark, MT; Liberty, MT; Madison, MT; Meagher, MT; Pondera, MT; Teton, MT; Toole, MT; Big Horn, MT; Carbon, MT; Musselshell, MT; Rosebud, MT; Treasure, MT; Yellowstone, MT; Golden Valley, MT; Park, MT; Stillwater, MT; Sweet Grass, MT; Wheatland, MT and 1 more areas |
| Headline | Severe Thunderstorm Watch issued May 13 at 8:52PM MDT until May 13 at 9:00PM MDT by NWS Great Falls MT |
| Expires | 2026-05-13T22:00:00-06:00 |
| SenderName | NWS Great Falls MT |
| HasExactCoords | false |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.376de6773b9edb8b92068270d0c7ecac49753ff9.001.1","noaa_urn:oid:2.49.0.1.840.0.b162847e99f2eb87b2e29344279ae213d9e207be.002.1","noaa_urn:oid:2.49.0.1.840.0.b162847e99f2eb87b2e29344279ae213d9e207be.001.1","noaa_urn:oid:2.49.0.1.840.0.f7f2a0eaba14e0c4be04ce047d800d41de3a567a.002.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 59 |
| Iem Unit | MPH |
| Iem City | 17 NE Wilsall |
| Iem County | Park |
| Iem State | MT |
| Iem Wfo | BYZ |
| Iem Remark | Mesonet station TT453 Crazy. |
| MergedSources | [{"id":"iem_G_47.280_-110.800_1778705700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778705700000,"latitude":47.28,"longitude":-110.8},{"id":"iem_G_47.250_-110.480_1778706000000","source":"iem","severity":"low","severityValue":25,"timestamp":1778706000000,"latitude":47.25,"longitude":-110.48},{"id":"iem_G_46.690_-109.750_1778713260000","source":"iem","severity":"low","severityValue":25,"timestamp":1778713260000,"latitude":46.69,"longitude":-109.75},{"id":"iem_N_46.160_-110.380_1778721120000","source":"iem","severity":"low","severityValue":25,"timestamp":1778721120000,"latitude":46.16,"longitude":-110.38},{"id":"iem_G_46.160_-110.380_1778724720000","source":"iem","severity":"low","severityValue":25,"timestamp":1778724720000,"latitude":46.16,"longitude":-110.38}] |
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 in this area?
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 185 scientific monitoring sources.