Right now
The most recent data we hold from NOAA arrived 4 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 31 July 2026 at 05:30 UTC. It is kept here as a record.
No stronger detection stands among the 34 recorded within 20 km of this point since 15 March 2026 — 6 others scored the same. The last comparable one was on 26 July 2026. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued July 30 at 6:25PM CDT until July 31 at 12:30AM CDT by NWS Aberdeen SD
How we know
6 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 22 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.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 22 / 100 |
| Legacy data-support index | 0.71/1 |
| Coordinates | 45.5513, -97.0400 |
| Nearest City | Watertown (73 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-07-30T23:25:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.1c5bbcf78a047e71ff4aa29c4d0c88dbb28510db.001.1 |
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: 2026-07-30T23:25:00.000Z.
First archived: 2026-07-31T04:29:21.412Z. 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 | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Big Stone, MN; Traverse, MN; Day, SD; Marshall, SD; Roberts, SD |
| Headline | Flash Flood Warning issued July 30 at 6:25PM CDT until July 31 at 12:30AM CDT by NWS Aberdeen SD |
| Expires | 2026-07-31T00:30:00-05:00 |
| SenderName | NWS Aberdeen SD |
| HasExactCoords | true |
| Iem TypeSummary | R |
| Iem Magnitude | 5 |
| Iem Unit | Inch |
| Iem City | 2 SE Roslyn |
| Iem County | Day |
| Iem State | SD |
| Iem Wfo | ABR |
| MergedSources | [{"id":"iem_F_45.500_-97.490_1785448680000","source":"iem","severity":"low","severityValue":25,"timestamp":1785448680000,"latitude":45.5,"longitude":-97.49},{"id":"iem_R_45.500_-97.830_1785448800000","source":"iem","severity":"low","severityValue":25,"timestamp":1785448800000,"latitude":45.5,"longitude":-97.83},{"id":"iem_F_45.490_-97.840_1785448680000","source":"iem","severity":"low","severityValue":25,"timestamp":1785448680000,"latitude":45.49,"longitude":-97.84},{"id":"iem_R_45.500_-97.830_1785446580000","source":"iem","severity":"low","severityValue":25,"timestamp":1785446580000,"latitude":45.5,"longitude":-97.83},{"id":"iem_R_45.480_-97.460_1785446400000","source":"iem","severity":"low","severityValue":25,"timestamp":1785446400000,"latitude":45.48,"longitude":-97.46}] |
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.
Review the area, threshold and delivery channel in your account.
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