Calamity
MediumSevere WeatherCalamity Score: 28

Severe Weather in United States

United StatesNOAA

This alert expired on 4 September 2026 at 15:46 UTC. It is kept here as a record.

It is the 11th strongest of the 12 detections recorded within 20 km of this point since 10 March 2026. Another comparable one was recorded here earlier the same day.

What the source measured

NOAA reported: Special Marine Warning issued September 4 at 11:36AM EDT until September 4 at 11:45AM EDT by NWS Grand Rapids MI

An estimated 33,742 people live within 50 km of this point.

Nearby, since 10 March 2026

How we know

Confirmed by 2 independent sources, including NOAA.

Our own score for this event is 28 out of 100, at 87 % 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)28 / 100
Our confidence87%
Coordinates42.7100, -86.5344
Nearest CityHolland (36 km)
Population Exposed33.7K within 50 km
Impact Tiersignificant
Timestamp2026-09-04T15:36:00.000Z
Sourcehttps://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.eb67a93188b2579f77a1903e0f02dc096ccfb6e2.001.1

Score Breakdown

35
intensity
40
population
0
cascading
18
historical

Technical Details

EventSpecial Marine Warning
UrgencyImmediate
CertaintyLikely
AreaDescSouth Haven to Holland MI; Holland to Grand Haven MI; Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake; Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake
HeadlineSpecial Marine Warning issued September 4 at 11:36AM EDT until September 4 at 11:45AM EDT by NWS Grand Rapids MI
Expires2026-09-04T11:46:00-04:00
SenderNameNWS Grand Rapids MI
HasExactCoordstrue
Iem TypeSummaryR
Iem Magnitude1.22
Iem UnitInch
Iem City1 WSW Grandville
Iem CountyKent
Iem StateMI
Iem WfoGRR
Iem RemarkMesonet station CW1502 Grandville.
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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.

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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 185 scientific monitoring sources.