This alert expired on 4 September 2026 at 03:45 UTC. It is kept here as a record.
It is the 181st strongest of the 220 detections recorded within 20 km of this point since 13 March 2026. The last comparable one was on 10 August 2026.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 3 at 11:20PM EDT until September 3 at 11:45PM EDT by NWS Baltimore MD/Washington DC
An estimated 4,146,983 people live within 50 km of this point.
Nearby, since 13 March 2026
- September 4, 2026 · score 46 · 3.9 km
- March 17, 2026 · score 52 · 4.4 km
- March 16, 2026 · score 52 · 4.4 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 46 out of 100, at 92 % 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) | 46 / 100 |
| Our confidence | 92% |
| Coordinates | 38.9304, -77.3211 |
| Nearest City | Wolf Trap (3 km) |
| Population Exposed | 4.1M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-04T03:20:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.15e99123417497573ad1433004cc4fc5f6297fb2.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Arlington, VA; Fairfax, VA; City of Alexandria, VA; City of Fairfax, VA; City of Falls Church, VA; Montgomery, MD; Fairfax, VA; Loudoun, VA; Fairfax, VA; Loudoun, VA; Prince William, VA; City of Manassas, VA; City of Manassas Park, VA |
| Headline | Severe Thunderstorm Warning issued September 3 at 11:20PM EDT until September 3 at 11:45PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-09-03T23:45:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.15e99123417497573ad1433004cc4fc5f6297fb2.001.1","noaa_urn:oid:2.49.0.1.840.0.6bcee8226bb8c6c0303f7658c0921df12f512b40.001.1","noaa_urn:oid:2.49.0.1.840.0.55997e2a6bed21980192a991e0762e8ad469d921.001.1"] |
| Spc ReportType | wind |
| Spc Speed | UNK |
| Spc Location | 3 E Buckeystown |
| Spc County | Frederick |
| Spc State | MD |
| Spc Comments | Tree down along Park Mills Road. Time estimated via radar. (LWX) |
| Iem TypeSummary | D |
| Iem City | Frederick |
| Iem County | Frederick |
| Iem State | MD |
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 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 Wolf Trap?
Calamity.live data shows a weather event with CalamityScore 46/100, near Wolf Trap (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.