This alert expired on 21 July 2026 at 21:15 UTC. It is kept here as a record.
It is the 28th strongest of the 53 detections recorded within 20 km of this point since 17 March 2026. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued July 21 at 4:23PM EDT until July 21 at 5:15PM EDT by NWS Baltimore MD/Washington DC
An estimated 49,516 people live within 50 km of this point.
Nearby, since 17 March 2026
- July 23, 2026 · score 34 · 7.6 km
- March 21, 2026 · score 34 · 16.8 km
- June 22, 2026 · score 58 · 17.8 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 28 out of 100, at 79 % 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) | 28 / 100 |
| Our confidence | 79% |
| Coordinates | 38.3352, -76.0301 |
| Nearest City | Salisbury (38 km) |
| Population Exposed | 49.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-21T20:23:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.4ed913b827abb2900dd7164b8f1979b0 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Tidal Potomac from Key Bridge to Indian Head MD; Tidal Potomac from Indian Head to Cobb Island MD; Chesapeake Bay from Drum Point MD to Smith Point VA; Tangier Sound and the inland waters surrounding Bloodsworth Island; Tidal Potomac from Indian Head to Cobb Island MD; Tidal Potomac from Cobb Island MD to Smith Point VA and 1 more areas |
| Headline | Special Marine Warning issued July 21 at 4:23PM EDT until July 21 at 5:15PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-07-21T17:15:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.4ed913b827abb2900dd7164b8f1979b09ec90db3.001.1","noaa_urn:oid:2.49.0.1.840.0.4f058a6b2419538828dd721cfd96be2511845815.001.1","noaa_urn:oid:2.49.0.1.840.0.7396e4073b1970660a4b3a776bb3a3665d3b4cd3.001.1","noaa_urn:oid:2.49.0.1.840.0.cb53676565460baa0f17e8a2b975d90f39060050.001.1"] |
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 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 28/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.