This alert expired on 18 May 2026 at 00:45 UTC. It is kept here as a record.
No stronger detection stands among the 56 recorded within 20 km of this point since 15 March 2026 — 2 others scored the same. The last comparable one was on 15 May 2026. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Tornado Warning issued May 17 at 7:24PM CDT until May 17 at 7:45PM CDT by NWS Sioux Falls SD
Nearby, since 15 March 2026
- June 30, 2026 · score 28 · 11.9 km
- June 24, 2026 · score 22 · 20.1 km
- May 25, 2026 · score 22 · 23.8 km
How we know
Confirmed by 14 independent sources, including NOAA.
Our own score for this event is 46 out of 100, at 70 % 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 | 70% |
| Coordinates | 43.2712, -95.2966 |
| Nearest City | Sioux Falls (120 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-18T00:24:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Tornado Warning_noaa_urn:oid:2.49.0.1.840.0.1d4d8096da75bd2a4f4dfa45bbec819b |
Score Breakdown
Technical Details
| Event | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Cottonwood, MN; Jackson, MN; Blue Earth, MN; Martin, MN; Watonwan, MN; Thurston, NE |
| Headline | Tornado Warning issued May 17 at 7:24PM CDT until May 17 at 7:45PM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-17T19:45:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.1d4d8096da75bd2a4f4dfa45bbec819b54311606.001.1","noaa_urn:oid:2.49.0.1.840.0.c9cd9ae849705af60d88ab8db1d2a3db7c93a0d3.001.1","noaa_urn:oid:2.49.0.1.840.0.7ac70c45e7494b413e71a56ff5c4caee936b9837.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 55 |
| Iem Unit | MPH |
| Iem City | 2 ENE Worthington |
| Iem County | Nobles |
| Iem State | MN |
| Iem Wfo | FSD |
| Iem Remark | AWOS station KOTG Worthington Airport. |
| MergedSources | [{"id":"iem_C_43.700_-95.960_1779058080000","source":"iem","severity":"low","severityValue":25,"timestamp":1779058080000,"latitude":43.7,"longitude":-95.96},{"id":"iem_H_43.840_-95.590_1779060120000","source":"iem","severity":"low","severityValue":25,"timestamp":1779060120000,"latitude":43.84,"longitude":-95.59},{"id":"iem_H_43.570_-95.650_1779059880000","source":"iem","severity":"low","severityValue":25,"timestamp":1779059880000,"latitude":43.57,"longitude":-95.65},{"id":"iem_H_43.650_-95.930_1779058200000","source":"iem","severity":"low","severityValue":25,"timestamp":1779058200000,"latitude":43.65,"longitude":-95.93},{"id":"iem_H_43.410_-95.750_1779060960000","source":"iem","severity":"low","severityValue":25,"timestamp":1779060960000,"latitude":43.41,"longitude":-95.75},{"id":"iem_H_43.750_-95.950_1779058440000","source":"iem","severity":"low","severityValue":25,"timestamp":1779058440000,"latitude":43.75,"longitude":-95.95},{"id":"iem_G_43.680_-95.890_1779057840000","source":"iem","severity":"low","severityValue":25,"timestamp":1779057840000,"latitude":43.68,"longitude":-95.89},{"id":"iem_H_43.870_-95.600_1779060240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779060240000,"latitude":43.87,"longitude":-95.6},{"id":"iem_H_43.760_-95.830_1779058860000","source":"iem","severity":"low","severityValue":25,"timestamp":1779058860000,"latitude":43.76,"longitude":-95.83},{"id":"iem_H_43.600_-96.090_1779057360000","source":"iem","severity":"low","severityValue":25,"timestamp":1779057360000,"latitude":43.6,"longitude":-96.09},{"id":"iem_G_43.650_-95.590_1779060360000","source":"iem","severity":"low","severityValue":25,"timestamp":1779060360000,"latitude":43.65,"longitude":-95.59},{"id":"iem_T_43.600_-95.640_1779059700000","source":"iem","severity":"low","severityValue":25,"timestamp":1779059700000,"latitude":43.6,"longitude":-95.64},{"id":"iem_G_43.630_-95.570_1779060360000","source":"iem","severity":"low","severityValue":25,"timestamp":1779060360000,"latitude":43.63,"longitude":-95.57}] |
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.