This alert expired on 6 July 2026 at 01:00 UTC. It is kept here as a record.
It is the 6th strongest of the 168 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. 16 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 5 at 8:43PM EDT until July 5 at 9:00PM EDT by NWS Baltimore MD/Washington DC
An estimated 1,167,777 people live within 50 km of this point.
Nearby, since 12 March 2026
- July 6, 2026 · score 52 · 9.2 km
- July 9, 2026 · score 52 · 10.0 km
- March 12, 2026 · score 48 · 10.1 km
How we know
Confirmed by 9 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 88 % 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 | 88% |
| Coordinates | 39.4295, -77.3335 |
| Nearest City | Frederick (7 km) |
| Population Exposed | 1.2M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-06T00:43:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.affcd013f25a49a9c7df53dbfcb42806 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Frederick, VA; Page, VA; Shenandoah, VA; Warren, VA; City of Winchester, VA; Page, VA; Rockingham, VA; City of Harrisonburg, VA; Frederick, VA and 7 more areas |
| Headline | Severe Thunderstorm Warning issued July 5 at 8:43PM EDT until July 5 at 9:00PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-07-05T21:00:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 10 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.affcd013f25a49a9c7df53dbfcb4280679cb542f.001.1","noaa_urn:oid:2.49.0.1.840.0.00fd02bbf8cc09b7ec0bd71c93d91be74d77d558.001.1","noaa_urn:oid:2.49.0.1.840.0.b4a05278f6f10137a473aec7d6078f0b8d2c8963.001.1","noaa_urn:oid:2.49.0.1.840.0.fc20ab3a77e30d57eb6f0b27dce5feef72b07ccb.002.1","noaa_urn:oid:2.49.0.1.840.0.e32ef616baf4987da60c14c75041983eef680cee.001.1","noaa_urn:oid:2.49.0.1.840.0.c0697a24ce4f2070cfc11e4dd4a0f3c8696e2687.001.1","noaa_urn:oid:2.49.0.1.840.0.7e087474f8105cff7cca967738c72408b203fd84.002.1","noaa_urn:oid:2.49.0.1.840.0.2fb0103f8eec33ba25133f747388b05e9f2b35d1.001.1","noaa_urn:oid:2.49.0.1.840.0.6b852930b0a791048ed838d596dd15157879a93a.001.1","noaa_urn:oid:2.49.0.1.840.0.3823fa5d1979bd0225df8e7693fa0c50b6fe920f.001.1"] |
| Iem TypeSummary | D |
| Iem City | Reston |
| Iem County | Fairfax |
| Iem State | VA |
| Iem Wfo | LWX |
| Iem Remark | Tree down onto a home in the 1000 block of Old Reston Ave. Numerous other reorts of trees and large diameter brances down in the area east of Reston Town Center around Baron Cameron Ave. |
| MergedSources | [{"id":"iem_D_39.150_-77.050_1783294020000","source":"iem","severity":"low","severityValue":25,"timestamp":1783294020000,"latitude":39.15,"longitude":-77.05},{"id":"iem_D_39.160_-77.050_1783291380000","source":"iem","severity":"low","severityValue":25,"timestamp":1783291380000,"latitude":39.16,"longitude":-77.05},{"id":"iem_D_39.230_-77.120_1783290960000","source":"iem","severity":"low","severityValue":25,"timestamp":1783290960000,"latitude":39.23,"longitude":-77.12},{"id":"iem_D_38.970_-77.340_1783294500000","source":"iem","severity":"low","severityValue":25,"timestamp":1783294500000,"latitude":38.97,"longitude":-77.34},{"id":"iem_D_38.980_-77.380_1783294680000","source":"iem","severity":"low","severityValue":25,"timestamp":1783294680000,"latitude":38.98,"longitude":-77.38},{"id":"iem_G_39.180_-77.100_1783292760000","source":"iem","severity":"low","severityValue":25,"timestamp":1783292760000,"latitude":39.18,"longitude":-77.1},{"id":"iem_D_39.220_-77.060_1783291560000","source":"iem","severity":"low","severityValue":25,"timestamp":1783291560000,"latitude":39.22,"longitude":-77.06},{"id":"iem_D_38.960_-77.350_1783294500000","source":"iem","severity":"low","severityValue":25,"timestamp":1783294500000,"latitude":38.96,"longitude":-77.35}] |
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 52/100, near Frederick (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.