This alert expired on 2 September 2026 at 00:15 UTC. It is kept here as a record.
No stronger detection stands among the 22 recorded within 20 km of this point since 17 May 2026 — 8 others scored the same. The last comparable one was on 1 September 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 1 at 7:05PM CDT until September 1 at 7:15PM CDT by NWS Sioux Falls SD
Nearby, since 17 May 2026
- September 1, 2026 · score 28 · 24.0 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 28 out of 100, at 65 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | high |
| Calamity Score (ours) | 28 / 100 |
| Our confidence | 65% |
| Coordinates | 42.7577, -98.4351 |
| Nearest City | Mitchell (111 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-02T00:05:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.0a2b601a4800392bb848c219969e7b5c8d3e1905.002.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Bon Homme, SD; Charles Mix, SD; Hutchinson, SD; Boyd, NE; Holt, NE; Antelope, NE; Knox, NE and 1 more areas |
| Headline | Severe Thunderstorm Warning issued September 1 at 7:05PM CDT until September 1 at 7:15PM CDT by NWS Sioux Falls SD |
| Expires | 2026-09-01T19:15:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.0a2b601a4800392bb848c219969e7b5c8d3e1905.002.1","noaa_urn:oid:2.49.0.1.840.0.c841079e988e9a98ff3c1a636d8578a886ca1578.001.1","noaa_urn:oid:2.49.0.1.840.0.53920563034dee11d6dc9a9384658f5ef717d296.001.1","noaa_urn:oid:2.49.0.1.840.0.c6c38b862d5782785ce91503ee8702a6c9ec903d.001.1","noaa_urn:oid:2.49.0.1.840.0.49663463d47b426d0205e3c7f413cd3b2ff27c24.001.1"] |
| Spc ReportType | hail |
| Spc Speed | 175 |
| Spc Location | 1 WSW Marty |
| Spc County | Charles Mix |
| Spc State | SD |
| Spc Comments | In addition to golf ball sized hail... winds were gusting at 40-50 mph... and rainfall was heavy. (FSD) |
| MergedSources | [{"id":"spc_wind_42.84_-99.27_0","source":"spc","severity":"medium","severityValue":45,"timestamp":1788307849089,"latitude":42.84,"longitude":-99.27},{"id":"spc_wind_42.84_-99.26_1","source":"spc","severity":"medium","severityValue":45,"timestamp":1788307849089,"latitude":42.84,"longitude":-99.26},{"id":"spc_wind_43.09_-98.32_22","source":"spc","severity":"medium","severityValue":45,"timestamp":1788307849089,"latitude":43.09,"longitude":-98.32},{"id":"spc_wind_43.09_-98.32_24","source":"spc","severity":"medium","severityValue":45,"timestamp":1788307849089,"latitude":43.09,"longitude":-98.32},{"id":"spc_hail_42.95_-99.04_28","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":42.95,"longitude":-99.04},{"id":"spc_hail_43.02_-98.89_29","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":43.02,"longitude":-98.89},{"id":"spc_hail_43.02_-98.68_31","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":43.02,"longitude":-98.68},{"id":"spc_hail_43.07_-98.53_32","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":43.07,"longitude":-98.53},{"id":"spc_hail_43.06_-98.53_33","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":43.06,"longitude":-98.53},{"id":"spc_hail_42.98_-98.82_34","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":42.98,"longitude":-98.82},{"id":"spc_hail_43.13_-98.35_35","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":43.13,"longitude":-98.35},{"id":"spc_hail_42.70_-99.14_38","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":42.7,"longitude":-99.14},{"id":"spc_hail_42.84_-98.87_39","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":42.84,"longitude":-98.87},{"id":"spc_hail_42.99_-98.44_40","source":"spc","severity":"high","severityValue":65,"timestamp":1788307849089,"latitude":42.99,"longitude":-98.44}] |
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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 28/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.