Right now
The most recent data we hold from NOAA arrived 42 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
2 other detections within 20 km in the last 24 hours, the nearest 20 km from here.
This alert expired on 17 May 2026 at 21:15 UTC. It is kept here as a record.
No stronger detection stands among the 54 recorded within 20 km of this point since 13 April 2026 — 3 others scored the same. The last comparable one was on 13 April 2026.
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
How we know
Confirmed by 9 independent sources, including NOAA.
Our own score for this event is 46 out of 100, at 69 % 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 | 69% |
| Coordinates | 43.1771, -97.4543 |
| Nearest City | Sioux Falls (71 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-17T20:23:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.ae5e1167386076978a8ea930f762c08d6c7c66d9.001.1 |
Score Breakdown
Technical Details
| Event | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Hutchinson, SD; Turner, SD; Yankton, 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 |
| Iem TypeSummary | D |
| Iem City | 2 W Avon |
| Iem County | Bon Homme |
| Iem State | SD |
| Iem Wfo | FSD |
| Iem Remark | Trained spotter reported a shed with its roof blown off. |
| MergedSources | [{"id":"iem_G_43.070_-98.300_1779047280000","source":"iem","severity":"low","severityValue":25,"timestamp":1779047280000,"latitude":43.07,"longitude":-98.3},{"id":"iem_G_43.000_-97.970_1779048000000","source":"iem","severity":"low","severityValue":25,"timestamp":1779048000000,"latitude":43,"longitude":-97.97},{"id":"iem_D_43.070_-98.330_1779046800000","source":"iem","severity":"low","severityValue":25,"timestamp":1779046800000,"latitude":43.07,"longitude":-98.33},{"id":"iem_G_43.080_-98.130_1779047520000","source":"iem","severity":"low","severityValue":25,"timestamp":1779047520000,"latitude":43.08,"longitude":-98.13},{"id":"iem_D_43.070_-98.330_1779047160000","source":"iem","severity":"low","severityValue":25,"timestamp":1779047160000,"latitude":43.07,"longitude":-98.33},{"id":"iem_G_43.070_-98.310_1779046800000","source":"iem","severity":"low","severityValue":25,"timestamp":1779046800000,"latitude":43.07,"longitude":-98.31},{"id":"iem_D_43.080_-98.190_1779047400000","source":"iem","severity":"low","severityValue":25,"timestamp":1779047400000,"latitude":43.08,"longitude":-98.19},{"id":"iem_D_43.010_-98.100_1779047640000","source":"iem","severity":"low","severityValue":25,"timestamp":1779047640000,"latitude":43.01,"longitude":-98.1}] |
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.