This alert expired on 2 September 2026 at 20:34 UTC. It is kept here as a record.
It is the 2nd strongest of the 6 detections recorded within 20 km of this point since 24 April 2026. The last comparable one was on 29 June 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 2 at 2:24PM MDT until September 2 at 2:30PM MDT by NWS Great Falls MT
An estimated 32,091 people live within 50 km of this point.
Nearby, since 24 April 2026
- May 27, 2026 · score 39 · 16.6 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 28 out of 100, at 91 % 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 | Medium |
| Calamity Score (ours) | 28 / 100 |
| Our confidence | 91% |
| Coordinates | 46.4626, -112.3828 |
| Nearest City | Helena (30 km) |
| Population Exposed | 32.1K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-02T20:24:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.3ab58eecfc1819cf50802a30643fb8ca15b6797d.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Jefferson, MT; Madison, MT; Broadwater, MT; Jefferson, MT; Lewis and Clark, MT; Lewis and Clark, MT |
| Headline | Severe Thunderstorm Warning issued September 2 at 2:24PM MDT until September 2 at 2:30PM MDT by NWS Great Falls MT |
| Expires | 2026-09-02T14:34:00-06:00 |
| SenderName | NWS Great Falls MT |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.3ab58eecfc1819cf50802a30643fb8ca15b6797d.001.1","noaa_urn:oid:2.49.0.1.840.0.ea497f37de2138c112a1eef308f9dc3234ed6dab.001.1","noaa_urn:oid:2.49.0.1.840.0.d9a98a91a0a552ebc9a3613b913fe0954c32199e.001.1"] |
| Spc ReportType | wind |
| Spc Speed | 74 |
| Spc Location | 3 NNE Newcomb |
| Spc County | Silver Bow |
| Spc State | MT |
| Spc Comments | Bert Mooney Airport ASOS. (MSO) |
| Iem TypeSummary | G |
| Iem Magnitude | 58 |
| Iem Unit | MPH |
| Iem City | 4 NNW Opportunity |
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 Helena?
Calamity.live data shows a weather event with CalamityScore 28/100, near Helena (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.