This alert expired on 21 July 2026 at 21:30 UTC. It is kept here as a record.
It is the 4th strongest of the 15 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 23 June 2026.
What the source measured
NOAA reported: Special Marine Warning issued July 21 at 4:34PM EDT until July 21 at 5:30PM EDT by NWS Boston/Norton MA
An estimated 636,677 people live within 50 km of this point.
Nearby, since 16 March 2026
- July 22, 2026 · score 52 · 12.4 km
- August 13, 2026 · score 48 · 21.0 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 41 out of 100, at 79 % 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) | 41 / 100 |
| Our confidence | 79% |
| Coordinates | 41.6239, -70.8367 |
| Nearest City | Fairhaven (6 km) |
| Population Exposed | 636.7K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-21T20:34:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.7195651c72d716a15c37172bd0f697a01c5d8b3e.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Cape Cod Bay; Nantucket Sound; Vineyard Sound; Buzzards Bay; Rhode Island Sound; Narragansett Bay; Coastal waters from Provincetown MA to Chatham MA to Nantucket MA out 20 NM; Coastal Waters extending out to 25 NM South of Marthas Vineyard and Nantucket; Coastal Waters from Montauk NY to Marthas Vineyard extending out to 20 NM South of Block Island |
| Headline | Special Marine Warning issued July 21 at 4:34PM EDT until July 21 at 5:30PM EDT by NWS Boston/Norton MA |
| Expires | 2026-07-21T17:30:00-04:00 |
| SenderName | NWS Boston/Norton MA |
| HasExactCoords | true |
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 Fairhaven?
Calamity.live data shows a weather event with CalamityScore 41/100, near Fairhaven (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.