Calamity
MediumSevere WeatherCalamity Score: 22

Severe Weather in United States

Sweet GrassUnited StatesNOAA

Right now

The most recent data we hold from NOAA arrived 2 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 13 May 2026 at 23:00 UTC. It is kept here as a record.

No stronger detection stands among the 30 recorded within 20 km of this point since 15 March 2026 — 2 others scored the same. The last comparable one was on 7 May 2026. One more was recorded here in the fortnight before it.

What the source measured

NOAA reported: Severe Thunderstorm Warning issued May 13 at 3:58PM MDT until May 13 at 5:00PM MDT by NWS Billings MT

How we know

Confirmed by 17 independent sources, including NOAA.

Our own score for this event is 22 out of 100, at 70 % 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)22 / 100
Our confidence70%
Coordinates46.0012, -109.9435
Nearest CityBozeman (92 km)
Impact Tierminor
Timestamp2026-05-13T21:58:00.000Z
Sourcehttps://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.eb4bdb63259df0e8f5b334fbc9b84d74fd938db5.001.1

Score Breakdown

35
intensity
0
population
0
cascading
80
historical

Technical Details

EventSevere Thunderstorm Warning
UrgencyImmediate
CertaintyObserved
AreaDescPark, MT; Stillwater, MT; Sweet Grass, MT
HeadlineSevere Thunderstorm Warning issued May 13 at 3:58PM MDT until May 13 at 5:00PM MDT by NWS Billings MT
Expires2026-05-13T17:00:00-06:00
SenderNameNWS Billings MT
HasExactCoordstrue
Iem TypeSummaryN
Iem Magnitude56
Iem UnitMPH
Iem City1 SSE Livingston
Iem CountyPark
Iem StateMT
Iem WfoBYZ
Iem RemarkMesonet station MTLRH Livingston River Hill.
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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 22/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.