Calamity
MediumSevere WeatherCalamity Score: 48

Severe Weather in United States

St. ClairUnited StatesNOAA

Right now

The most recent data we hold from NOAA arrived 17 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.

Nothing else has been detected within 20 km in the last 24 hours.

This alert expired on 18 May 2026 at 22:15 UTC. It is kept here as a record.

It is the 33rd strongest of the 55 detections recorded within 20 km of this point since 4 April 2026. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.

What the source measured

NOAA reported: Special Marine Warning issued May 18 at 5:57PM EDT until May 18 at 6:15PM EDT by NWS Gaylord MI

An estimated 663,052 people live within 50 km of this point.

Nearby, since 4 April 2026

How we know

Confirmed by 7 independent sources, including NOAA.

Our own score for this event is 48 out of 100, at 89 % 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

TypeSevere Weather
SeverityMedium
Calamity Score (ours)48 / 100
Our confidence89%
Coordinates42.9837, -82.9021
Nearest CityShelby (36 km)
Population Exposed663.1K within 50 km
Impact Tiersignificant
Timestamp2026-05-18T21:57:00.000Z
Sourcehttps://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.eb3488ab2cd91f3dd16173076549eab9

Score Breakdown

35
intensity
85
population
0
cascading
80
historical

Technical Details

EventSpecial Marine Warning
UrgencyImmediate
CertaintyLikely
AreaDescSturgeon Pt to Alabaster MI; Lake Huron from Sturgeon Point to Alabaster MI 5NM off shore to US/Canadian border; Presque Isle Light to Sturgeon Pt MI Including Thunder Bay National Marine Sanctuary; Sturgeon Pt to Alabaster MI; Lake Huron from Presque Isle Lt. to Sturgeon Point MI 5NM off shore to US/Canadian border; Lake Huron from Sturgeon Point to Alabaster MI 5NM off shore to US/Canadian border; St. Clair River; Port Austin to Harbor Beach MI; Harbor Beach to Port Sanilac MI; Port Sanilac to Port Huron MI; Lake Huron from Port Austin to Harbor Beach 5NM Off Shore to the US/Canadian border; Lake Huron from Harbor Beach to Port Sanilac 5NM Off Shore to US/Canadian border; Lake Huron from Port Sanilac to Port Huron 5NM Off Shore to US/Canadian border and 3 more areas
HeadlineSpecial Marine Warning issued May 18 at 5:57PM EDT until May 18 at 6:15PM EDT by NWS Gaylord MI
Expires2026-05-18T18:15:00-04:00
SenderNameNWS Gaylord MI
HasExactCoordstrue
MergedCount6
MergedIds["noaa_urn:oid:2.49.0.1.840.0.eb3488ab2cd91f3dd16173076549eab974db4c54.001.1","noaa_urn:oid:2.49.0.1.840.0.7bba9aaf3f1e0fee483824f5836213ee6e03884b.001.1","noaa_urn:oid:2.49.0.1.840.0.4e9315d6435fcbfd0aa25b81933a05101b60d712.001.1","noaa_urn:oid:2.49.0.1.840.0.f7725e83da72fb033e3f9e32b8f706bd6f3959e7.001.1","noaa_urn:oid:2.49.0.1.840.0.1e577237abf9bb50e43f5f264f1e4d94fb4c4ba9.001.1","noaa_urn:oid:2.49.0.1.840.0.6a211a7d492e4ed53dc7457b0bc8e87a0548812e.001.1"]
Iem TypeSummaryG
Iem Magnitude58
Iem Unitmph
Iem CityOakland County Intl Air
Iem CountyOakland
Iem StateMI
Iem WfoDTX
Iem RemarkMeasured at KPTK Pontiac Airport
MergedSources[{"id":"iem_D_43.220_-83.430_1779137400000","source":"iem","severity":"low","severityValue":25,"timestamp":1779137400000,"latitude":43.22,"longitude":-83.43},{"id":"iem_D_42.660_-83.170_1779132240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779132240000,"latitude":42.66,"longitude":-83.17},{"id":"iem_D_42.620_-83.030_1779139140000","source":"iem","severity":"low","severityValue":25,"timestamp":1779139140000,"latitude":42.62,"longitude":-83.03},{"id":"iem_G_42.410_-83.010_1779139080000","source":"iem","severity":"low","severityValue":25,"timestamp":1779139080000,"latitude":42.41,"longitude":-83.01},{"id":"iem_D_42.640_-83.070_1779139140000","source":"iem","severity":"low","severityValue":25,"timestamp":1779139140000,"latitude":42.64,"longitude":-83.07},{"id":"iem_G_42.660_-83.410_1779137100000","source":"iem","severity":"low","severityValue":25,"timestamp":1779137100000,"latitude":42.66,"longitude":-83.41}]

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 48/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.