This alert expired on 17 March 2026 at 02:45 UTC. It is kept here as a record.
It is the 62nd strongest of the 201 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 16 March 2026. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued March 16 at 8:46PM EDT until March 16 at 10:45PM EDT by NWS Baltimore MD/Washington DC
An estimated 755,615 people live within 50 km of this point.
Nearby, since 16 March 2026
- July 5, 2026 · score 48 · 2.4 km
- July 28, 2026 · score 41 · 4.2 km
- July 4, 2026 · score 48 · 5.7 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 48 out of 100, at 88 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 48 / 100 |
| Our confidence | 88% |
| Coordinates | 38.6968, -76.4468 |
| Nearest City | Greater Upper Marlboro (30 km) |
| Population Exposed | 755.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-03-17T00:46:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.e922c83a7f38068f3e715dc8fd9b04ac |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Chesapeake Bay from Sandy Point to North Beach MD; Chesapeake Bay from North Beach to Drum Point MD; Chesapeake Bay from Drum Point MD to Smith Point VA; Tidal Potomac from Cobb Island MD to Smith Point VA; Eastern Bay; Choptank River to Cambridge MD and the Little Choptank River; Patuxent River to Broomes Island MD; Tangier Sound and the inland waters surrounding Bloodsworth Island; Chesapeake Bay north of Pooles Island MD; Chesapeake Bay from Pooles Island to Sandy Point MD; Chesapeake Bay from Sandy Point to North Beach MD; Patapsco River including Baltimore Harbor; Chester River to Queenstown MD; Eastern Bay; 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 March 16 at 8:46PM EDT until March 16 at 10:45PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-03-16T22:45:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.e922c83a7f38068f3e715dc8fd9b04acc82915c5.001.1","noaa_urn:oid:2.49.0.1.840.0.6f06305c73cea93ba0b0c8ba019841752ea2aeef.001.1","noaa_urn:oid:2.49.0.1.840.0.2f1b26b6cb93d13550a8b5948e84341edcf4df7e.001.1"] |
| Spc ReportType | wind |
| Spc Speed | UNK |
| Spc Location | Hyattsville |
| Spc County | Prince Georges |
| Spc State | MD |
| Spc Comments | Tree fell on a vehicle at the 6400 block of Kilmer Street (LWX) |
| MergedSources | [{"id":"spc_wind_38.54_-77.08_142","source":"spc","severity":"medium","severityValue":45,"timestamp":1773708890561,"latitude":38.54,"longitude":-77.08},{"id":"spc_wind_38.89_-76.87_149","source":"spc","severity":"medium","severityValue":45,"timestamp":1773708890561,"latitude":38.89,"longitude":-76.87}] |
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 Greater Upper Marlboro?
Calamity.live data shows a weather event with CalamityScore 48/100, near Greater Upper Marlboro (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.