Right now
The most recent data we hold from NOAA arrived 2 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
One other detection within 20 km in the last 24 hours, 16 km from here.
This alert expired on 6 September 2026 at 23:19 UTC. It is kept here as a record.
It is the 12th strongest of the 23 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Flash Flood Warning issued September 6 at 6:09PM CDT until September 6 at 6:15PM CDT by NWS Sioux Falls SD
Nearby, since 16 March 2026
- August 13, 2026 · score 46 · 8.5 km
- May 15, 2026 · score 22 · 12.0 km
- May 18, 2026 · score 46 · 12.2 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 16 out of 100, at 70 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 16 / 100 |
| Our confidence | 70% |
| Coordinates | 42.1517, -95.4126 |
| Nearest City | Sioux City (90 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-06T23:09:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.c3d7e50658c2142aaf5c2693fb7fbe6b24cd9de7.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Cherokee, IA; Shelby, IA; Crawford, IA |
| Headline | Flash Flood Warning issued September 6 at 6:09PM CDT until September 6 at 6:15PM CDT by NWS Sioux Falls SD |
| Expires | 2026-09-06T18:19:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.c3d7e50658c2142aaf5c2693fb7fbe6b24cd9de7.001.1","noaa_urn:oid:2.49.0.1.840.0.9dd001de44f9edf430679760b487b91af65f0fa2.001.1","noaa_urn:oid:2.49.0.1.840.0.8e31e2260193ef0992e9e8ac48558b24236e1185.001.1"] |
| Spc ReportType | wind |
| Spc Speed | 60 |
| Spc Location | 3 W Kirkman |
| Spc County | Shelby |
| Spc State | IA |
| Spc Comments | Public report of thunderstorm wind gusts estimated at 50-60 mph... breaking a few large tree branches. (OAX) |
| Iem TypeSummary | R |
| Iem Magnitude | 4.16 |
| Iem Unit | Inch |
| Iem City | Denison |
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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 16/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.