This alert expired on 28 June 2026 at 06:31 UTC. It is kept here as a record.
No stronger detection stands among the 19 recorded within 20 km of this point since 14 May 2026 — 11 others scored the same. Another comparable one was recorded here earlier the same day. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued June 28 at 12:21AM MDT until June 28 at 12:30AM MDT by NWS Glasgow MT
An estimated 26,977 people live within 50 km of this point.
Nearby, since 14 May 2026
- July 4, 2026 · score 34 · 6.6 km
- July 3, 2026 · score 34 · 19.7 km
How we know
Confirmed by 19 independent sources, including NOAA.
Our own score for this event is 34 out of 100, at 90 % 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) | 34 / 100 |
| Our confidence | 90% |
| Coordinates | 48.1730, -104.2050 |
| Nearest City | Williston (43 km) |
| Population Exposed | 27.0K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-28T06:21:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.c5146b707b1aa26a3a54bb92973934c6e49e1eac.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Roosevelt, MT |
| Headline | Flash Flood Warning issued June 28 at 12:21AM MDT until June 28 at 12:30AM MDT by NWS Glasgow MT |
| Expires | 2026-06-28T00:31:00-06:00 |
| SenderName | NWS Glasgow MT |
| HasExactCoords | true |
| Iem TypeSummary | G |
| Iem Magnitude | 67 |
| Iem Unit | MPH |
| Iem City | 8 NNE Grenora |
| Iem County | Divide |
| Iem State | ND |
| Iem Wfo | BIS |
| Iem Remark | 67 MPH gust at 10M measured at 8N Grenora NDAWN. |
| MergedSources | [{"id":"iem_G_48.620_-103.940_1782613740000","source":"iem","severity":"low","severityValue":25,"timestamp":1782613740000,"latitude":48.62,"longitude":-103.94},{"id":"iem_R_47.700_-104.600_1782614400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782614400000,"latitude":47.7,"longitude":-104.6},{"id":"iem_G_48.560_-103.690_1782613860000","source":"iem","severity":"low","severityValue":25,"timestamp":1782613860000,"latitude":48.56,"longitude":-103.69},{"id":"iem_H_47.860_-104.920_1782606120000","source":"iem","severity":"low","severityValue":25,"timestamp":1782606120000,"latitude":47.86,"longitude":-104.92},{"id":"iem_G_48.490_-104.480_1782611880000","source":"iem","severity":"low","severityValue":25,"timestamp":1782611880000,"latitude":48.49,"longitude":-104.48},{"id":"iem_F_48.190_-104.580_1782615600000","source":"iem","severity":"low","severityValue":25,"timestamp":1782615600000,"latitude":48.19,"longitude":-104.58},{"id":"iem_D_48.150_-103.670_1782613200000","source":"iem","severity":"low","severityValue":25,"timestamp":1782613200000,"latitude":48.15,"longitude":-103.67},{"id":"iem_G_47.700_-104.730_1782610200000","source":"iem","severity":"low","severityValue":25,"timestamp":1782610200000,"latitude":47.7,"longitude":-104.73},{"id":"iem_G_48.260_-103.910_1782612360000","source":"iem","severity":"low","severityValue":25,"timestamp":1782612360000,"latitude":48.26,"longitude":-103.91},{"id":"iem_R_48.310_-105.100_1782612000000","source":"iem","severity":"low","severityValue":25,"timestamp":1782612000000,"latitude":48.31,"longitude":-105.1},{"id":"iem_G_48.340_-103.860_1782612660000","source":"iem","severity":"low","severityValue":25,"timestamp":1782612660000,"latitude":48.34,"longitude":-103.86},{"id":"iem_G_47.700_-104.730_1782611760000","source":"iem","severity":"low","severityValue":25,"timestamp":1782611760000,"latitude":47.7,"longitude":-104.73},{"id":"iem_G_47.940_-103.790_1782611100000","source":"iem","severity":"low","severityValue":25,"timestamp":1782611100000,"latitude":47.94,"longitude":-103.79},{"id":"iem_G_48.260_-104.500_1782610200000","source":"iem","severity":"low","severityValue":25,"timestamp":1782610200000,"latitude":48.26,"longitude":-104.5},{"id":"iem_G_47.970_-103.930_1782611100000","source":"iem","severity":"low","severityValue":25,"timestamp":1782611100000,"latitude":47.97,"longitude":-103.93},{"id":"iem_G_48.270_-103.750_1782612900000","source":"iem","severity":"low","severityValue":25,"timestamp":1782612900000,"latitude":48.27,"longitude":-103.75},{"id":"iem_R_47.950_-104.940_1782613800000","source":"iem","severity":"low","severityValue":25,"timestamp":1782613800000,"latitude":47.95,"longitude":-104.94},{"id":"iem_G_48.740_-103.880_1782614400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782614400000,"latitude":48.74,"longitude":-103.88}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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 34/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.