This alert expired on 4 July 2026 at 22:30 UTC. It is kept here as a record.
It is the 155th strongest of the 235 detections recorded within 20 km of this point since 15 March 2026. The last comparable one was on 25 June 2026. 7 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued July 4 at 2:26PM CDT until July 4 at 5:30PM CDT by NWS St Louis MO
An estimated 1,359,526 people live within 50 km of this point.
Nearby, since 15 March 2026
- June 8, 2026 · score 52 · 8.6 km
- July 13, 2026 · score 52 · 10.7 km
- July 4, 2026 · score 52 · 13.3 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 82 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 52 / 100 |
| Our confidence | 82% |
| Coordinates | 38.7876, -90.3190 |
| Nearest City | Florissant (0 km) |
| Population Exposed | 1.4M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-04T19:26:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.2e8eb7bf3ce28da90f44ee048256ca0e53f0e7d4.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | St. Louis, MO; St. Louis City, MO |
| Headline | Flash Flood Warning issued July 4 at 2:26PM CDT until July 4 at 5:30PM CDT by NWS St Louis MO |
| Expires | 2026-07-04T17:30:00-05:00 |
| SenderName | NWS St Louis MO |
| HasExactCoords | true |
| Iem TypeSummary | D |
| Iem City | 2 E Weldon Spring |
| Iem County | St. Charles |
| Iem State | MO |
| Iem Wfo | LSX |
| Iem Remark | Power lines down. |
| MergedSources | [{"id":"iem_D_38.720_-90.600_1783196100000","source":"iem","severity":"low","severityValue":25,"timestamp":1783196100000,"latitude":38.72,"longitude":-90.6}] |
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 10 February 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.
Calamity.live data shows a weather event with CalamityScore 52/100, near Florissant (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.