Right now
The most recent data we hold from NOAA arrived 3 minutes ago.
Nothing else has been detected within 20 km in the last 24 hours.
This page covers the record dated 31 May 2026. Browse recent observations in this area:
This alert expired on 31 May 2026 at 23:45 UTC. It is kept here as a record.
No stronger detection stands among the 35 recorded within 20 km of this point since 25 May 2026 — one other scored the same. Another comparable one was recorded here earlier the same day. 7 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Tornado Warning issued May 31 at 6:07PM CDT until May 31 at 6:45PM CDT by NWS Sioux Falls SD
Urban PEI: 15,669 within a heuristic 50 km radius; not unique people.
Nearby, since 25 May 2026
- May 31, 2026 · score 58 · 2.1 km
- July 1, 2026 · score 22 · 2.8 km
- May 31, 2026 · score 46 · 3.1 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 58 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
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.
Event data
| Type | Severe Weather |
| Severity | Critical |
| Calamity Score (ours) | 58 / 100 |
| Legacy data-support index | 0.79/1 |
| Coordinates | 43.5900, -97.4500 |
| Nearest city | Mitchell (49 km) |
| Urban exposure index (PEI) | 15.7K within 50 km |
| Impact tier | significant |
| Timestamp | 2026-05-31T23:07:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.cafbbf5d74d2cd0c75fff33ccd503cf904e8677f.001.1 |
| Licence | US public domain · NOAA National Weather Service |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-05-31T23:07:00.000Z.
First archived: 2026-05-31T23:16:09.159Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score breakdown
Technical details
| Event | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | McCook, SD |
| Headline | Tornado Warning issued May 31 at 6:07PM CDT until May 31 at 6:45PM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-31T18:45:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
Safety information
What to do in a tornado
Three things first, then what to do before, during and after. From FEMA’s Ready.gov and the US National Weather Service.
For this reportSevere Weather · United States
Go to the lowest, innermost room
A basement or a storm shelter; otherwise an inner room without windows on the lowest floor. Protect your head and neck.
Ready.govLeave a mobile home
It gives no protection: go to a sturdy building or a shelter before the tornado arrives.
Ready.govOutdoors or in a car
Find the strongest shelter you can. If there is none, lie flat in a low place and cover your head. Never under a bridge.
Ready.gov
Before, during, after. Here it is “after”.
Before · When tornadoes are possible
Get the warnings
Phone alerts and weather radio, day and night.
Choose your safe room
Lowest floor, inner, no windows; everyone at home should know it.
Know the signs
A rotating cloud, a cloud of debris, a loud roar like a train.
Ready.gov (FEMA)
During · When a warning is issued
Go now
To your safe room, without waiting to see it.
Cover up
Arms over head and neck; blankets or a mattress over you.
Ready.gov (FEMA)
After · When it has passed
Keep away from fallen lines
And from damaged buildings.
Clean up protected
Sturdy shoes, gloves, a mask.
Messages, not calls
Keep lines free for emergencies.
Ready.gov (FEMA)
Questions people ask
What is the difference between a tornado watch and a warning?
A watch means tornadoes are possible: be ready. A warning means one has been seen or detected on radar: take shelter now. Source: US National Weather Service.
Should I open the windows?
No. It does not help, and it wastes time you need to take shelter. Source: US National Weather Service.
Is an overpass a good shelter?
No. Wind speeds up under it and carries debris. Source: Ready.gov (FEMA).
Review the area, threshold and delivery channel in your account.