A closed low pressure system over Washington and Oregon drew arctic air west of the Continental Divide which caused sub-freezing temperatures, periods of snow, and slick road conditions.

Winter Storm in MISSOULA / BITTERROOT VALLEYS, MONTANA
From 25-OCT-23 02:00:00 to 25-OCT-23 12:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Rain followed by snow, along with falling temperatures into the 20s and gusty easterly winds to 30 mph caused flash freezing of the roadways. A CoCoRaHS observer in the South Hills reported 0.25 inches of ice underneath the 3.1 inches of snow. Other snow amounts include 3.8 inches Lolo and 6 inches on the grass 2 miles north of Wye. A secondary storm brought very heavy snow rates of 1 to 2 inches per hour to the Darby area during the evening of the 25th. A person from the public reported 10 inches of total snowfall in Darby.

Winter Storm in LOWER CLARK FORK REGION, MONTANA
From 24-OCT-23 22:00:00 to 25-OCT-23 12:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Flash freezing of roadways developed as 1 to 2 inches of snow fell on already wet roads and temperatures fell into the 20s.

Winter Storm in BUTTE / BLACKFOOT REGION, MONTANA
From 24-OCT-23 19:30:00 to 26-OCT-23 10:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Flash freeze of roadways occurred as rain changed to snow with falling temperatures into the teens. Gusty north to east winds between 20 and 40 mph caused periods of blowing snow with reduced visibility along and west of the Divide. Snow amounts include 6 inches in Ovando, 8 inches west of Anaconda and Philipsburg through the morning of the 25th. A secondary storm brought an additional 11 inches of snow to Anaconda and the 2 day total of 19 inches became the 2nd highest on record.  Butte received a total of 7.3 inches out of both storms. A plethora of vehicle accidents and semi jackknifes occurred during this time period.

Winter Storm in BITTERROOT / SAPPHIRE MOUNTAINS, MONTANA
From 24-OCT-23 21:00:00 to 25-OCT-23 13:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Rain developed on the evening of the 24th which set the stage for a flash freeze situation as rain changed to snow and temperatures fell into the low to mid 20s by daybreak on the 25th. Lolo Pass received 9 inches of total snowfall.

Winter Weather in FLATHEAD/MISSION VALLEYS, MONTANA
From 24-OCT-23 13:00:00 to 25-OCT-23 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Light snow between 1 and 3 inches fell across the Flathead and Mission valleys with slick roads reported by a weather spotter. MDT reported 6 to 8 inches of lake effect snow fell on the southeast side of Flathead Lake on the 27th and 28th. A large arctic steam devil as high as 300 feet tall was reported and photographed near Wood's Bay on the 29th by a person from the public.

Winter Storm in POTOMAC / SEELEY LAKE REGION, MONTANA
From 24-OCT-23 21:00:00 to 25-OCT-23 14:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Rain changed to snow as temperatures fell into the 20s and winds gusted to 35 mph which caused flash freezing of the roadways. A COOP in Potomac reported 4 inches of snow. A semi rolled over east of Clearwater Junction and caused Highway 200 to closed for a period during the afternoon of the 25th.

Winter Weather in KOOTENAI/CABINET REGION, MONTANA
From 24-OCT-23 13:00:00 to 25-OCT-23 13:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Between 4 and 8 inches of snow fell between Happy's Inn and Kila during the event.

Winter Storm in WEST GLACIER REGION, MONTANA
From 24-OCT-23 02:00:00 to 25-OCT-23 13:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Heavy snow and gusty winds occurred and caused roads to be slick with ice underneath the snow. A weather spotter in Hungry Horse and COOP in West Glacier both reported 9 inches of snowfall during the event.