Right now
The most recent data we hold from NOAA arrived 2 hours 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 1 June 2026 at 03:15 UTC. It is kept here as a record.
It is the 25th strongest of the 40 detections recorded within 20 km of this point since 8 April 2026. Another comparable one was recorded here earlier the same day. 11 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued May 31 at 7:10PM CDT until May 31 at 10:15PM CDT by NWS Aberdeen SD
Nearby, since 8 April 2026
- May 31, 2026 · score 40 · 4.8 km
- June 1, 2026 · score 40 · 19.3 km
How we know
Confirmed by 10 independent sources, including NOAA.
Our own score for this event is 28 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 | High |
| Calamity Score (ours) | 28 / 100 |
| Our confidence | 69% |
| Coordinates | 45.6820, -99.0540 |
| Nearest City | Aberdeen (50 km) |
| Impact Tier | minor |
| Timestamp | 2026-06-01T00:10:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.ce1e04ff7351876b6b6b7a15446fe3a2c87c0fb9.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | McPherson, SD |
| Headline | Flash Flood Warning issued May 31 at 7:10PM CDT until May 31 at 10:15PM CDT by NWS Aberdeen SD |
| Expires | 2026-05-31T22:15:00-05:00 |
| SenderName | NWS Aberdeen SD |
| HasExactCoords | true |
| Spc ReportType | hail |
| Spc Speed | 100 |
| Spc Location | 3 SSW Leola |
| Spc County | McPherson |
| Spc State | SD |
| Spc Comments | (ABR) |
| Iem TypeSummary | F |
| Iem City | 2 W Leola |
| Iem County | McPherson |
| Iem State | SD |
| Iem Wfo | ABR |
| Iem Remark | Official with Leola Fire reports 6-12 inches of water covering SD 10 just west of town. Heavy equipment brought in to try and push the water off the roadway. |
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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