Right now
The most recent data we hold from NOAA arrived 9 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 25 May 2026 at 07:15 UTC. It is kept here as a record.
It is the 10th strongest of the 63 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 20 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued May 24 at 11:29PM CDT until May 25 at 2:15AM CDT by NWS Sioux Falls SD
An estimated 171,544 people live within 50 km of this point.
Nearby, since 15 March 2026
- May 25, 2026 · score 43 · 0.0 km
- May 17, 2026 · score 67 · 16.7 km
- July 1, 2026 · score 43 · 19.9 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 90 % 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 | Medium |
| Calamity Score (ours) | 43 / 100 |
| Our confidence | 90% |
| Coordinates | 43.5220, -96.7190 |
| Nearest City | Sioux Falls (2 km) |
| Population Exposed | 171.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-25T04:29:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.1e6a8068de82c6f265e2d029ffca83d433d389ee.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Minnehaha, SD |
| Headline | Flash Flood Warning issued May 24 at 11:29PM CDT until May 25 at 2:15AM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-25T02:15:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| Iem TypeSummary | H |
| Iem Magnitude | 1.5 |
| Iem Unit | Inch |
| Iem City | Freeman |
| Iem County | Hutchinson |
| Iem State | SD |
| Iem Wfo | FSD |
| Iem Remark | Freeman Fire Rescue reported pea to Ping-Pong ball sized hail in Freeman. Time was estimated via radar. |
| MergedSources | [{"id":"iem_H_43.220_-97.510_1779670860000","source":"iem","severity":"low","severityValue":25,"timestamp":1779670860000,"latitude":43.22,"longitude":-97.51},{"id":"iem_H_43.350_-97.430_1779674700000","source":"iem","severity":"low","severityValue":25,"timestamp":1779674700000,"latitude":43.35,"longitude":-97.43}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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.
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