This alert expired on 4 September 2026 at 09:45 UTC. It is kept here as a record.
It is the 3rd strongest of the 108 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 4 at 2:40AM EDT until September 4 at 5:45AM EDT by NWS Pittsburgh PA
An estimated 690,465 people live within 50 km of this point.
Nearby, since 16 March 2026
- September 4, 2026 · score 54 · 0.0 km
- August 28, 2026 · score 41 · 5.3 km
- August 27, 2026 · score 41 · 7.0 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 54 out of 100, at 91 % 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 | High |
| Calamity Score (ours) | 54 / 100 |
| Our confidence | 91% |
| Coordinates | 40.3265, -80.1347 |
| Nearest City | Upper Saint Clair (5 km) |
| Population Exposed | 690.5K within 50 km |
| Impact Tier | severe |
| Timestamp | 2026-09-04T06:40:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.5d590b1f7e7ce3be7ead46f9265db14f07b966e6.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Jefferson, OH; Allegheny, PA; Washington, PA; Brooke, WV; Hancock, WV |
| Headline | Flash Flood Warning issued September 4 at 2:40AM EDT until September 4 at 5:45AM EDT by NWS Pittsburgh PA |
| Expires | 2026-09-04T05:45:00-04:00 |
| SenderName | NWS Pittsburgh PA |
| HasExactCoords | true |
| Spc ReportType | hail |
| Spc Speed | 150 |
| Spc Location | 1 SW Braddock |
| Spc County | Allegheny |
| Spc State | PA |
| Spc Comments | (PBZ) |
| Iem TypeSummary | R |
| Iem Magnitude | 1.75 |
| Iem Unit | Inch |
| Iem City | Dormont |
| Iem County | Allegheny |
| Iem State | PA |
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 near Upper Saint Clair?
Calamity.live data shows a weather event with CalamityScore 54/100, near Upper Saint Clair (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.