This alert expired on 18 May 2026 at 22:15 UTC. It is kept here as a record.
No stronger detection stands among the 31 recorded within 20 km of this point since 4 April 2026 — 8 others scored the same. Another comparable one was recorded here earlier the same day. 5 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 18 at 5:24PM EDT until May 18 at 6:15PM EDT by NWS Detroit/Pontiac MI
An estimated 1,338,194 people live within 50 km of this point.
Nearby, since 4 April 2026
- June 11, 2026 · score 46 · 10.1 km
- May 18, 2026 · score 52 · 12.2 km
- July 4, 2026 · score 52 · 15.2 km
How we know
Confirmed by 8 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 89 % 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) | 52 / 100 |
| Our confidence | 89% |
| Coordinates | 42.8496, -83.0270 |
| Nearest City | Shelby (20 km) |
| Population Exposed | 1.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-18T21:24:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.2b61f34f418d775e6bf2cfbf433f71b7 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Sanilac, MI; Oakland, MI; Wayne, MI; Macomb, MI; St. Clair, MI and 3 more areas |
| Headline | Severe Thunderstorm Warning issued May 18 at 5:24PM EDT until May 18 at 6:15PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-18T18:15:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| MergedCount | 6 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.2b61f34f418d775e6bf2cfbf433f71b7656a61cb.001.1","noaa_urn:oid:2.49.0.1.840.0.31142af95d8edfaa4a78eb51ac6a80fabe0432d6.001.1","noaa_urn:oid:2.49.0.1.840.0.1a8fb08369322572defc58f99ce1a2f41d294565.001.1","noaa_urn:oid:2.49.0.1.840.0.855dcd0e831954e358c2f514aa6c900d3896ebd1.001.1","noaa_urn:oid:2.49.0.1.840.0.266a6170efc5c9ea2080d79b13a3767652dbef1d.001.1","noaa_urn:oid:2.49.0.1.840.0.1d272335a8d503067401092c93dee50a0d16c322.001.1"] |
| Iem TypeSummary | D |
| Iem City | 1 NW Rochester Hills |
| Iem County | Oakland |
| Iem State | MI |
| Iem Wfo | DTX |
| Iem Remark | Report of large tree limb down on house causing damage to roofing |
| Google News RssFeed | weather |
| Google News SourceName | ClickOnDetroit | WDIV Local 4 |
| MergedSources | [{"id":"iem_G_42.660_-83.410_1779137100000","source":"iem","severity":"low","severityValue":25,"timestamp":1779137100000,"latitude":42.66,"longitude":-83.41},{"id":"iem_D_42.660_-83.170_1779132240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779132240000,"latitude":42.66,"longitude":-83.17},{"id":"gnews_weather_494202_120","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779130324000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494203_121","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779131397000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494204_125","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779134883000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494203_131","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779133500000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494201_143","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779124179000,"latitude":42.33,"longitude":-83.05}] |
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 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.
Calamity.live data shows a weather event with CalamityScore 52/100, near Shelby (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.