This alert expired on 21 March 2026 at 00:30 UTC. It is kept here as a record.
It is the 71st strongest of the 194 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 106 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued March 20 at 7:40PM EDT until March 20 at 8:30PM EDT by NWS Baltimore MD/Washington DC
An estimated 265,548 people live within 50 km of this point.
Nearby, since 16 March 2026
- July 9, 2026 · score 43 · 7.8 km
- March 17, 2026 · score 72 · 12.8 km
- July 18, 2026 · score 43 · 13.7 km
How we know
Confirmed by 8 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 91 % 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) | 43 / 100 |
| Our confidence | 91% |
| Coordinates | 38.5445, -76.4186 |
| Nearest City | Easton (39 km) |
| Population Exposed | 265.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-03-20T23:40:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.0c7ba1246650c8edf43bfb52f893cb6c |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Tidal Potomac from Indian Head to Cobb Island MD; Tidal Potomac from Cobb Island MD to Smith Point VA; 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; Chesapeake Bay from North Beach to Drum Point MD; Patapsco River including Baltimore Harbor; Chester River to Queenstown MD; Eastern Bay; Choptank River to Cambridge MD and the Little Choptank River; Chesapeake Bay from Drum Point MD to Smith Point VA; Patuxent River to Broomes Island MD; Tangier Sound and the inland waters surrounding Bloodsworth Island |
| Headline | Special Marine Warning issued March 20 at 7:40PM EDT until March 20 at 8:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-03-20T20:30:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.0c7ba1246650c8edf43bfb52f893cb6c79994ab7.001.1","noaa_urn:oid:2.49.0.1.840.0.ef063a1c4aa7fca7eea99c3d41304ee8b6bd4b27.001.1","noaa_urn:oid:2.49.0.1.840.0.17ab1139259c78c2a3168b663cfe6dc93f6bc035.001.1"] |
| Iem TypeSummary | M |
| Iem Magnitude | 40 |
| Iem Unit | mph |
| Iem City | 2 E Woodbridge |
| Iem County | ANZ536 |
| Iem State | VA |
| Iem Wfo | LWX |
| Iem Remark | A wind gust of 35 knots (40 MPH) was measured by the Occoquan River WeatherFlow sensor (XOCC). |
| MergedSources | [{"id":"iem_M_38.920_-77.090_1774045200000","source":"iem","severity":"low","severityValue":25,"timestamp":1774045200000,"latitude":38.92,"longitude":-77.09},{"id":"iem_M_38.340_-76.990_1774048920000","source":"iem","severity":"low","severityValue":25,"timestamp":1774048920000,"latitude":38.34,"longitude":-76.99},{"id":"iem_M_38.850_-77.030_1774045560000","source":"iem","severity":"low","severityValue":25,"timestamp":1774045560000,"latitude":38.85,"longitude":-77.03},{"id":"iem_M_38.640_-77.220_1774046220000","source":"iem","severity":"low","severityValue":25,"timestamp":1774046220000,"latitude":38.64,"longitude":-77.22},{"id":"iem_M_38.330_-77.020_1774048620000","source":"iem","severity":"low","severityValue":25,"timestamp":1774048620000,"latitude":38.33,"longitude":-77.02},{"id":"iem_M_38.340_-76.990_1774047120000","source":"iem","severity":"low","severityValue":25,"timestamp":1774047120000,"latitude":38.34,"longitude":-76.99},{"id":"iem_M_38.640_-77.220_1774045620000","source":"iem","severity":"low","severityValue":25,"timestamp":1774045620000,"latitude":38.64,"longitude":-77.22}] |
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 43/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.