This alert is in force until 4 September 2026, 05:00 UTC.
It is the 117th strongest of the 216 detections recorded within 20 km of this point since 17 March 2026. The last comparable one was on 2 September 2026.
What the source measured
NOAA reported: Special Marine Warning issued September 3 at 11:27PM EDT until September 4 at 1:00AM EDT by NWS Baltimore MD/Washington DC
An estimated 137,507 people live within 50 km of this point.
Nearby, since 17 March 2026
- September 4, 2026 · score 37 · 0.0 km
- July 21, 2026 · score 37 · 7.8 km
- August 3, 2026 · score 43 · 8.2 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 37 out of 100, at 82 % 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) | 37 / 100 |
| Our confidence | 82% |
| Coordinates | 38.2889, -76.7751 |
| Nearest City | Saint Charles (37 km) |
| Population Exposed | 137.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-04T03:27:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.adb87b55b347a97fbbb4b6316068dcd8279ba985.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Tidal Potomac from Cobb Island MD to Smith Point VA; Tidal Potomac from Key Bridge to Indian Head MD; Tidal Potomac from Indian Head to Cobb Island MD; Tidal Potomac from Cobb Island MD to Smith Point VA |
| Headline | Special Marine Warning issued September 3 at 11:27PM EDT until September 4 at 1:00AM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-09-04T01:00:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.adb87b55b347a97fbbb4b6316068dcd8279ba985.001.1","noaa_urn:oid:2.49.0.1.840.0.b1644aa1f74c835fb8a3aebbd9759aa4daae8b81.001.1"] |
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 in this area?
Calamity.live data shows a weather event with CalamityScore 37/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.