Calamity
MediumSevere WeatherCalamity Score: 37

Severe Weather in United States

ColletonUnited StatesNOAA

Right now

The most recent data we hold from NOAA arrived 2 minutes ago, and this point is in it.

One other detection within 20 km in the last 24 hours, <1 km from here.

This alert expired on 11 September 2026 at 22:32 UTC. It is kept here as a record.

It is the 6th strongest of the 31 detections recorded within 20 km of this point since 12 June 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: Flash Flood Warning issued September 11 at 6:22PM EDT until September 11 at 6:30PM EDT by NWS Charleston SC

An estimated 348,391 people live within 50 km of this point.

Nearby, since 12 June 2026

How we know

Confirmed by 2 independent sources, including NOAA.

Our own score for this event is 37 out of 100, at 85 % confidence.

The score is ours, computed from intensity, exposed population and local history — not the source’s.

Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.

Event Data

TypeSevere Weather
SeverityMedium
Calamity Score (ours)37 / 100
Our confidence85%
Coordinates32.7856, -80.4422
Nearest CitySummerville (36 km)
Population Exposed348.4K within 50 km
Impact Tiersignificant
Timestamp2026-09-11T22:22:00.000Z
Sourcehttps://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.b416a6f4ee125fdb24b09406062ef0a94ecbe950.001.1

Score Breakdown

35
intensity
70
population
0
cascading
18
historical

Technical Details

EventFlash Flood Warning
UrgencyImmediate
CertaintyLikely
AreaDescCharleston, SC; Colleton, SC
HeadlineFlash Flood Warning issued September 11 at 6:22PM EDT until September 11 at 6:30PM EDT by NWS Charleston SC
Expires2026-09-11T18:32:00-04:00
SenderNameNWS Charleston SC
HasExactCoordstrue
Spc ReportTypewind
Spc SpeedUNK
Spc Location1 SSW West Ashley
Spc CountyCharleston
Spc StateSC
Spc CommentsSCDPS reports a tree down near the intersection of Pearlott St and Wappoo Rd. Time estimated from radar. (CHS)
MergedSources[{"id":"spc_wind_32.79_-80.02_1","source":"spc","severity":"medium","severityValue":45,"timestamp":1789155600000,"latitude":32.79,"longitude":-80.02}]

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 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.

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