This alert expired on 18 May 2026 at 21:15 UTC. It is kept here as a record.
No stronger detection stands among the 53 recorded within 20 km of this point since 31 March 2026 — 17 others scored the same. Another comparable one was recorded here earlier the same day. 9 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 18 at 4:57PM EDT until May 18 at 5:15PM EDT by NWS Detroit/Pontiac MI
An estimated 1,780,176 people live within 50 km of this point.
Nearby, since 31 March 2026
- May 9, 2026 · score 52 · 2.4 km
- June 16, 2026 · score 52 · 3.1 km
- June 16, 2026 · score 52 · 6.4 km
How we know
Confirmed by 7 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 | 42.7572, -83.3966 |
| Nearest City | Waterford (8 km) |
| Population Exposed | 1.8M within 50 km |
| Impact Tier | significant |
| Date | 2026-05-18 — time not reported by the source |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.376d13cf819247051bd73b6ebdab00c0 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Tuscola, MI; Monroe, MI; Sanilac, MI and 7 more areas |
| Headline | Severe Thunderstorm Warning issued May 18 at 4:57PM EDT until May 18 at 5:15PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-18T17:15:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| MergedCount | 10 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.376d13cf819247051bd73b6ebdab00c0d46e511e.001.1","noaa_urn:oid:2.49.0.1.840.0.b40df926aad9d229cddca8a1e2092aa2057dee3c.001.1","noaa_urn:oid:2.49.0.1.840.0.a09ff54477c0f5d7a8c8ccafc317e143e3140154.001.1","noaa_urn:oid:2.49.0.1.840.0.900015f8316398c28869d04236484e3d3864d292.001.1","noaa_urn:oid:2.49.0.1.840.0.4424aa5f9dc1c480c54e1b055b617a30f8c6a5bf.001.1","noaa_urn:oid:2.49.0.1.840.0.040ae71d28ba915a1aa3317b0350e34ea92542e0.001.1","noaa_urn:oid:2.49.0.1.840.0.bb37b469d4e8376236e2e1fd0a00f0cc705e46e6.001.1","noaa_urn:oid:2.49.0.1.840.0.b87ade078e0907622c98b46b088ef4cbced654ea.001.1","noaa_urn:oid:2.49.0.1.840.0.e5f00ad9cb800b231a0dba49a2bb9237fac78436.001.1","noaa_urn:oid:2.49.0.1.840.0.24639ea2e53c9ffab7b3a03a64bb5d5e941bdb02.001.1"] |
| 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_D_42.660_-83.170_1779132240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779132240000,"latitude":42.66,"longitude":-83.17},{"id":"gnews_weather_494202_117","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_494203_127","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779133500000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494204_131","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779134883000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494201_140","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 Waterford (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.