Right now
The most recent data we hold from NOAA arrived 2 minutes ago, and this point is in it.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 12 September 2026 at 00:45 UTC. It is kept here as a record.
It is the 5th strongest of the 8 detections recorded within 20 km of this point since 4 April 2026. The last comparable one was on 8 July 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 11 at 6:54PM CDT until September 11 at 7:45PM CDT by NWS Sioux Falls SD
Nearby, since 4 April 2026
- June 5, 2026 · score 22 · 2.5 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 16 out of 100, at 66 % 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) | 16 / 100 |
| Our confidence | 66% |
| Coordinates | 45.2973, -96.2415 |
| Nearest City | Watertown (82 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-11T23:54:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.61292845487a3ba1102d7c9d67f59445500bfbd3.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Lincoln, MN; Brookings, SD; Lake, SD; Moody, SD; Stevens, MN; Grant, MN |
| Headline | Severe Thunderstorm Warning issued September 11 at 6:54PM CDT until September 11 at 7:45PM CDT by NWS Sioux Falls SD |
| Expires | 2026-09-11T19:45:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.61292845487a3ba1102d7c9d67f59445500bfbd3.001.1","noaa_urn:oid:2.49.0.1.840.0.ead2b542698e6fb7ff7b24bd30f429e23c098f17.001.1","noaa_urn:oid:2.49.0.1.840.0.de33b8d18d3f0ad49ecc9b67ea614400de437e70.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 1.25 |
| Iem Unit | Inch |
| Iem City | 4.8 SW Herman |
| Iem County | Grant |
| Iem State | MN |
| Iem Wfo | FGF |
| MergedSources | [{"id":"iem_H_45.790_-96.320_1789169340000","source":"iem","severity":"low","severityValue":25,"timestamp":1789169340000,"latitude":45.79,"longitude":-96.32},{"id":"iem_H_45.790_-96.320_1789169820000","source":"iem","severity":"low","severityValue":25,"timestamp":1789169820000,"latitude":45.79,"longitude":-96.32},{"id":"iem_H_45.760_-96.210_1789169880000","source":"iem","severity":"low","severityValue":25,"timestamp":1789169880000,"latitude":45.76,"longitude":-96.21}] |
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.
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