Calamity
MediumSevere WeatherCalamity Score: 22

Severe Weather in United States

Sweet GrassUnited StatesNOAA

Right now

The most recent data we hold from NOAA arrived 14 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 14 May 2026 at 01:15 UTC. It is kept here as a record.

No stronger detection stands among the 43 recorded within 20 km of this point since 17 March 2026 — 3 others scored the same. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.

What the source measured

NOAA reported: Severe Thunderstorm Warning issued May 13 at 6:43PM MDT until May 13 at 7:15PM MDT by NWS Billings MT

How we know

Confirmed by 24 independent sources, including NOAA.

Our own score for this event is 22 out of 100, at 71 % 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 confidence71%
Coordinates45.6330, -109.5941
Nearest CityBillings (87 km)
Impact Tierminor
Timestamp2026-05-14T00:43:00.000Z
Sourcehttps://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.66d9a2d2d7defa02d085f9d1dd9d0c71

Score Breakdown

35
intensity
0
population
0
cascading
80
historical

Technical Details

EventSevere Thunderstorm Warning
UrgencyImmediate
CertaintyObserved
AreaDescCarbon, MT; Stillwater, MT; Sweet Grass, MT
HeadlineSevere Thunderstorm Warning issued May 13 at 6:43PM MDT until May 13 at 7:15PM MDT by NWS Billings MT
Expires2026-05-13T19:15:00-06:00
SenderNameNWS Billings MT
HasExactCoordstrue
MergedCount2
MergedIds["noaa_urn:oid:2.49.0.1.840.0.66d9a2d2d7defa02d085f9d1dd9d0c7165081fef.001.1","noaa_urn:oid:2.49.0.1.840.0.a37762535717e5b1dbbe11f7e824a40edfa43625.001.1"]
Iem TypeSummaryG
Iem Magnitude69
Iem UnitMPH
Iem City7 ENE Livingston
Iem CountyPark
Iem StateMT
Iem WfoBYZ
Iem RemarkASOS station KLVM Livingston.
MergedSources[{"id":"iem_G_46.130_-109.920_1778711460000","source":"iem","severity":"low","severityValue":25,"timestamp":1778711460000,"latitude":46.13,"longitude":-109.92},{"id":"iem_G_45.720_-110.250_1778709600000","source":"iem","severity":"low","severityValue":25,"timestamp":1778709600000,"latitude":45.72,"longitude":-110.25},{"id":"iem_G_45.640_-110.550_1778709600000","source":"iem","severity":"low","severityValue":25,"timestamp":1778709600000,"latitude":45.64,"longitude":-110.55},{"id":"iem_G_45.800_-109.970_1778710500000","source":"iem","severity":"low","severityValue":25,"timestamp":1778710500000,"latitude":45.8,"longitude":-109.97},{"id":"iem_G_45.580_-109.880_1778711700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778711700000,"latitude":45.58,"longitude":-109.88},{"id":"iem_N_45.640_-110.550_1778702400000","source":"iem","severity":"low","severityValue":25,"timestamp":1778702400000,"latitude":45.64,"longitude":-110.55},{"id":"iem_G_45.800_-109.430_1778711400000","source":"iem","severity":"low","severityValue":25,"timestamp":1778711400000,"latitude":45.8,"longitude":-109.43},{"id":"iem_N_45.640_-110.550_1778699700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778699700000,"latitude":45.64,"longitude":-110.55},{"id":"iem_N_45.030_-109.410_1778714700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778714700000,"latitude":45.03,"longitude":-109.41},{"id":"iem_N_45.640_-110.550_1778703300000","source":"iem","severity":"low","severityValue":25,"timestamp":1778703300000,"latitude":45.64,"longitude":-110.55},{"id":"iem_N_45.700_-110.430_1778701320000","source":"iem","severity":"low","severityValue":25,"timestamp":1778701320000,"latitude":45.7,"longitude":-110.43},{"id":"iem_G_45.700_-110.430_1778716380000","source":"iem","severity":"low","severityValue":25,"timestamp":1778716380000,"latitude":45.7,"longitude":-110.43},{"id":"iem_N_45.030_-109.410_1778700300000","source":"iem","severity":"low","severityValue":25,"timestamp":1778700300000,"latitude":45.03,"longitude":-109.41},{"id":"iem_N_45.640_-110.550_1778700600000","source":"iem","severity":"low","severityValue":25,"timestamp":1778700600000,"latitude":45.64,"longitude":-110.55},{"id":"iem_G_45.710_-109.580_1778711460000","source":"iem","severity":"low","severityValue":25,"timestamp":1778711460000,"latitude":45.71,"longitude":-109.58},{"id":"iem_G_45.640_-110.550_1778708700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778708700000,"latitude":45.64,"longitude":-110.55},{"id":"iem_N_45.700_-110.430_1778704800000","source":"iem","severity":"low","severityValue":25,"timestamp":1778704800000,"latitude":45.7,"longitude":-110.43},{"id":"iem_G_45.720_-110.250_1778717700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778717700000,"latitude":45.72,"longitude":-110.25},{"id":"iem_G_45.840_-109.950_1778710500000","source":"iem","severity":"low","severityValue":25,"timestamp":1778710500000,"latitude":45.84,"longitude":-109.95},{"id":"iem_G_45.690_-110.500_1778716800000","source":"iem","severity":"low","severityValue":25,"timestamp":1778716800000,"latitude":45.69,"longitude":-110.5},{"id":"iem_G_45.690_-110.500_1778708700000","source":"iem","severity":"low","severityValue":25,"timestamp":1778708700000,"latitude":45.69,"longitude":-110.5},{"id":"iem_G_46.040_-109.240_1778713200000","source":"iem","severity":"low","severityValue":25,"timestamp":1778713200000,"latitude":46.04,"longitude":-109.24},{"id":"iem_G_45.700_-110.430_1778709180000","source":"iem","severity":"low","severityValue":25,"timestamp":1778709180000,"latitude":45.7,"longitude":-110.43}]

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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