Right now
The most recent data we hold from NOAA arrived 7 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
4 other detections within 20 km in the last 24 hours, the nearest 4 km from here.
This alert expired on 20 September 2026 at 17:30 UTC. It is kept here as a record.
It is the 11th strongest of the 114 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 31 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued September 20 at 11:42AM EDT until September 20 at 1:30PM EDT by NWS Pittsburgh PA
Urban PEI: 690,015 within a heuristic 50 km radius; not unique people.
Nearby, since 16 March 2026
- September 13, 2026 · score 41 · 5.6 km
- September 12, 2026 · score 41 · 5.6 km
- September 13, 2026 · score 41 · 6.8 km
How we know
2 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 41 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 v5. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 41 / 100 |
| Legacy data-support index | 0.87/1 |
| Coordinates | 40.2163, -80.1737 |
| Nearest City | Upper Saint Clair (16 km) |
| Urban exposure index (PEI) | 690.0K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-20T15:42:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.31beba1e68848c9bb508cc343e3baf5ccf67797e.001.1 |
Physical priority index · v5. 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: 2026-09-20T15:42:00.000Z.
First archived: 2026-09-20T15:56:10.592Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
2026-09-20T16:50:03.879Z · data_change
Index 41 → 41; severity medium → medium; version 5 → 5.
2026-09-20T16:17:48.255Z · data_change
Index 41 → 41; severity medium → medium; version 5 → 5.
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Washington, PA |
| Headline | Flash Flood Warning issued September 20 at 11:42AM EDT until September 20 at 1:30PM EDT by NWS Pittsburgh PA |
| Expires | 2026-09-20T13:30:00-04:00 |
| SenderName | NWS Pittsburgh PA |
| HasExactCoords | true |
| Iem TypeSummary | F |
| Iem City | 1 NW Eighty Four |
| Iem County | Washington |
| Iem State | PA |
| Iem Wfo | PBZ |
| Iem Remark | Little Chartiers creek out of banks behind 84 Lumber Company Headquarters. Report from Social media. |
| MergedSources | [{"id":"iem_F_40.250_-80.050_1789916820000","source":"iem","severity":"low","severityValue":25,"timestamp":1789916820000,"latitude":40.25,"longitude":-80.05},{"id":"iem_R_40.120_-80.880_1789914780000","source":"iem","severity":"low","severityValue":25,"timestamp":1789914780000,"latitude":40.12,"longitude":-80.88},{"id":"iem_F_40.190_-80.140_1789920540000","source":"iem","severity":"low","severityValue":25,"timestamp":1789920540000,"latitude":40.19,"longitude":-80.14}] |
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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