This alert expired on 17 May 2026 at 21:15 UTC. It is kept here as a record.
It is the strongest of the 31 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Tornado Warning issued May 17 at 3:23PM CDT until May 17 at 4:15PM CDT by NWS Sioux Falls SD
Nearby, since 16 March 2026
- June 28, 2026 · score 34 · 21.6 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 46 out of 100, at 65 % 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 | Critical |
| Calamity Score (ours) | 46 / 100 |
| Our confidence | 65% |
| Coordinates | 43.1530, -97.7255 |
| Nearest City | Mitchell (67 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-17T20:23:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Tornado Warning_noaa_urn:oid:2.49.0.1.840.0.ae5e1167386076978a8ea930f762c08d |
Score Breakdown
Technical Details
| Event | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Hutchinson, SD; Turner, SD; Yankton, SD; Bon Homme, SD; Hutchinson, SD |
| Headline | Tornado Warning issued May 17 at 3:23PM CDT until May 17 at 4:15PM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-17T16:15:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.ae5e1167386076978a8ea930f762c08d6c7c66d9.001.1","noaa_urn:oid:2.49.0.1.840.0.aee3fe4c54946a3171da47b09769ddb39502c6fd.002.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 62 |
| Iem Unit | MPH |
| Iem City | 3 S Corsica |
| Iem County | Douglas |
| Iem State | SD |
| Iem Wfo | FSD |
| Iem Remark | Mesonet station 304 SD RWIS Corsica. |
| MergedSources | [{"id":"iem_G_43.380_-98.410_1779047400000","source":"iem","severity":"low","severityValue":25,"timestamp":1779047400000,"latitude":43.38,"longitude":-98.41}] |
Safety Information
If a tornado warning is issued: go to a basement or an interior room on the lowest floor, away from windows. A vehicle and a mobile home are not shelter. Cover your head and neck. Wait for the official all-clear before going outside, and watch for downed power lines and gas leaks afterwards.
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 46/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.