This alert expired on 9 August 2026 at 01:45 UTC. It is kept here as a record.
It is the 7th strongest of the 66 detections recorded within 20 km of this point since 17 March 2026. Another comparable one was recorded here earlier the same day. 22 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 8 at 9:00PM EDT until August 8 at 9:45PM EDT by NWS Pittsburgh PA
Nearby, since 17 March 2026
- August 3, 2026 · score 22 · 16.6 km
- July 18, 2026 · score 46 · 16.9 km
- July 19, 2026 · score 22 · 20.1 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 66 % 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) | 22 / 100 |
| Our confidence | 66% |
| Coordinates | 41.0004, -79.3202 |
| Nearest City | Plum (66 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-09T01:00:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.b10b2093310176192c4fcab5b6d6f580 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Clarion, PA; Jefferson, PA; Armstrong, PA; Butler, PA |
| Headline | Severe Thunderstorm Warning issued August 8 at 9:00PM EDT until August 8 at 9:45PM EDT by NWS Pittsburgh PA |
| Expires | 2026-08-08T21:45:00-04:00 |
| SenderName | NWS Pittsburgh PA |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.b10b2093310176192c4fcab5b6d6f580e069cd8c.001.1","noaa_urn:oid:2.49.0.1.840.0.c1e25544700c7be7bc257e677739ac0124e3ff46.001.1"] |
| Iem TypeSummary | D |
| Iem City | 5 ESE Harrisville |
| Iem County | Butler |
| Iem State | PA |
| Iem Wfo | PBZ |
| Iem Remark | Report and video of a snapped tree along Boyers Road. Time estimated based on radar. |
| MergedSources | [{"id":"iem_D_41.110_-79.930_1786233420000","source":"iem","severity":"low","severityValue":25,"timestamp":1786233420000,"latitude":41.11,"longitude":-79.93}] |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
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 22/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.