A slow-moving and very cold arctic air mass paused over northeast Montana and combined with winds around 10 mph to create multiple days of bitterly-cold wind chills.
Every event with a place to put it; 8 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GGW wrote it up.
A slow-moving and very cold arctic air mass paused over northeast Montana and combined with winds around 10 mph to create multiple days of bitterly-cold wind chills.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Glasgow, MT wrote its last area forecast discussion before the first event at Dec 5, 3:46 AM MST, 1 hour 24 minutes earlier.
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</html>The national radar mosaic for the moment the first event began.
8 extreme cold/wind chill. Local standard time, as filed.
The Comertown Turn-Off MT-5 DOT site recorded viable wind chills of 40 and 41 degrees below zero during this time.
The Navajo MT-5 DOT site recorded viable wind chills between 40 and 48 degrees below zero during this time, before failing mid-day on December 6th. Event end time is estimated to be 1 hour before warning expiration time.
The Comertown Turn-Off MT-5 DOT site recorded viable wind chills of 40 to 48 degrees below zero during this time.
Wind chills between 40 and 45 degrees below zero were recorded at the McDonalds MT-13 DOT site during this time.
Most sites in the area had slightly weaker winds and slightly warmer temperatures, but the conditions at the King Coulee RAWS site were enough to produce viable wind chills from 40 to 48 degrees below zero during this time.
Wind chills between 40 and 51 degrees below zero were recorded during this time. Event start time is based on observations from the McDonalds MT-13 DOT site. Event end time is base on observations from the Poplar AWOS site.
Sporadic wind chills with weaker winds were common across the area, but at the Commertown Turn-Off MT-5 DOT site, steady viable wind chills of 40 degrees below zero or worse were reported during this time. Although this observation site failed after 12:10 PM on the 6th, the event end time is estimated by the decrease in wind speeds observed at the Plentywood AWOS.
The Plentywood AWOS site recorded wind chills from 40 to 44 degrees below zero during this time with winds slightly below 10 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2013Every state in 2013This day in weather historyWarnings in Montana, December 2013
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 490000, 489999, 490001, 490003, 489997, 490004, 490002, 490007.