This alert expired on 3 August 2026 at 15:45 UTC. It is kept here as a record.
It is the 6th strongest of the 85 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 66 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued August 3 at 9:15AM EDT until August 3 at 11:45AM EDT by NWS Boston/Norton MA
An estimated 4,245,615 people live within 50 km of this point.
Nearby, since 16 March 2026
- March 17, 2026 · score 52 · 3.9 km
- June 18, 2026 · score 52 · 8.4 km
- May 19, 2026 · score 52 · 10.8 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 46 out of 100, at 87 % 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) | 46 / 100 |
| Our confidence | 87% |
| Coordinates | 42.4262, -71.6039 |
| Nearest City | Marlborough (10 km) |
| Population Exposed | 4.2M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-03T13:15:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.31e7a144fa523569e3ebddbf5ffb933f |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Bristol, MA; Bristol, RI; Kent, RI; Providence, RI; Washington, RI; Middlesex, MA; Worcester, MA; Hillsborough, NH; Merrimack, NH; Rockingham, NH; Strafford, NH |
| Headline | Flash Flood Warning issued August 3 at 9:15AM EDT until August 3 at 11:45AM EDT by NWS Boston/Norton MA |
| Expires | 2026-08-03T11:45:00-04:00 |
| SenderName | NWS Boston/Norton MA |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.31e7a144fa523569e3ebddbf5ffb933f96d8e7d7.001.1","noaa_urn:oid:2.49.0.1.840.0.323830892e5b5f8d9e395ed4e23f3f9ad78dc439.001.1","noaa_urn:oid:2.49.0.1.840.0.303764933f6801ce5d5e8caba7e8f17a36ff0760.001.1"] |
| Iem TypeSummary | F |
| Iem City | 3 NE Wilbraham |
| Iem County | Hampden |
| Iem State | MA |
| Iem Wfo | BOX |
| Iem Remark | In Palmer, Wilbraham St underpass was flooded and impassable. Relayed by amateur radio. |
| MergedSources | [{"id":"iem_F_42.150_-72.390_1785751800000","source":"iem","severity":"low","severityValue":25,"timestamp":1785751800000,"latitude":42.15,"longitude":-72.39}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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.
Want to know when something happens near Marlborough?
Calamity.live data shows a weather event with CalamityScore 46/100, near Marlborough (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.