This alert expired on 31 August 2026 at 00:06 UTC. It is kept here as a record.
No stronger detection stands among the 10 recorded within 20 km of this point since 28 June 2026 — 6 others scored the same. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 30 at 6:56PM CDT until August 30 at 7:00PM CDT by NWS Aberdeen SD
How we know
Confirmed by 5 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 70 % 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 | 70% |
| Coordinates | 46.3033, -101.4640 |
| Nearest City | Mandan (73 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-30T23:56:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Corson, SD; Burleigh, ND; Emmons, ND; Grant, ND; Morton, ND; Oliver, ND; Sioux, ND; Grant, ND; Morton, ND and 1 more areas |
| Headline | Severe Thunderstorm Warning issued August 30 at 6:56PM CDT until August 30 at 7:00PM CDT by NWS Aberdeen SD |
| Expires | 2026-08-30T19:06:00-05:00 |
| SenderName | NWS Aberdeen SD |
| HasExactCoords | true |
| MergedCount | 7 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.c8f6dbd236c7f07249374d521ab2f24444f805cd.001.1","noaa_urn:oid:2.49.0.1.840.0.713c977a02c4afc580a2d80ef61055edb5bb9dd4.001.1","noaa_urn:oid:2.49.0.1.840.0.e95e4b917ad486ddd4a156a87296f880dba45422.001.1","noaa_urn:oid:2.49.0.1.840.0.18b5a5971f46a0e6abc5814f18927ae544fac0e2.002.1","noaa_urn:oid:2.49.0.1.840.0.18b5a5971f46a0e6abc5814f18927ae544fac0e2.002.1","noaa_urn:oid:2.49.0.1.840.0.95583944599e1611968f6da01aeaea7cca553a73.001.1","noaa_urn:oid:2.49.0.1.840.0.95583944599e1611968f6da01aeaea7cca553a73.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 57 |
| Iem Unit | MPH |
| Iem City | 15 SSW Leith |
| Iem County | Grant |
| Iem State | ND |
| Iem Wfo | BIS |
| Iem Remark | NDAWN Station Pretty Rock 2E. Report at 10 meters, 45 MPH observed at the surface. |
| MergedSources | [{"id":"iem_G_45.900_-101.500_1788133560000","source":"iem","severity":"low","severityValue":25,"timestamp":1788133560000,"latitude":45.9,"longitude":-101.5},{"id":"iem_G_46.440_-101.370_1788133680000","source":"iem","severity":"low","severityValue":25,"timestamp":1788133680000,"latitude":46.44,"longitude":-101.37},{"id":"iem_G_46.500_-101.990_1788131760000","source":"iem","severity":"low","severityValue":25,"timestamp":1788131760000,"latitude":46.5,"longitude":-101.99},{"id":"iem_G_46.160_-101.770_1788132120000","source":"iem","severity":"low","severityValue":25,"timestamp":1788132120000,"latitude":46.16,"longitude":-101.77}] |
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.
Calamity.live data shows a weather event with CalamityScore 22/100, near Mandan (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.