This alert expired on 2 September 2026 at 02:15 UTC. It is kept here as a record.
No stronger detection stands among the 121 recorded within 20 km of this point since 16 March 2026 — 4 others scored the same. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Tornado Warning issued September 1 at 8:48PM CDT until September 1 at 9:15PM CDT by NWS Sioux Falls SD
Nearby, since 16 March 2026
- September 2, 2026 · score 46 · 4.7 km
- June 30, 2026 · score 28 · 10.7 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 46 out of 100, at 62 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | critical |
| Calamity Score (ours) | 46 / 100 |
| Our confidence | 62% |
| Coordinates | 42.8260, -97.1964 |
| Nearest City | Sioux City (75 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-02T01:48:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.c065c46ab9a47b3a0f2fa4be31bbc4d295e23ec0.001.1 |
Score Breakdown
Technical Details
| Event | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Clay, SD; Yankton, SD; Cedar, NE |
| Headline | Tornado Warning issued September 1 at 8:48PM CDT until September 1 at 9:15PM CDT by NWS Sioux Falls SD |
| Expires | 2026-09-01T21:15:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.c065c46ab9a47b3a0f2fa4be31bbc4d295e23ec0.001.1","noaa_urn:oid:2.49.0.1.840.0.76025f608fe8678052a3ece4ec68a210795fdb0c.001.1"] |
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 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 46/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.