A long duration snow event began Saturday evening Jan. 3 while snow intensities increased on Jan. 4 to produce widespread high impacts across western Montana and central Idaho. An Arctic front pushed west of the Continental Divide stalling from just south of Troy extending across Mineral County and the Missoula Valley and then southeast to Deer Lodge on Jan. 5. Areas along and north of this boundary helped to focus the moderate to heavy snowfall on Sunday. The plume of moisture with origins from the tropics, ran over the arctic air in place to cause very heavy amounts of snowfall across northwest Montana. As the front retreated northward on Jan. 5 locations across west-central Montana saw freezing rain that caused untreated surfaces to become slick.

Winter Storm in MISSOULA / BITTERROOT VALLEYS, MONTANA
From 04-JAN-15 19:00:00 to 05-JAN-15 14:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

After 6 inches of snow fell in the Missoula area, freezing rain developed and caused up to 0.25 of glaze to form on untreated surfaces. Numerous school delays or cancellations were made for the Missoula and Bitterroot Valley school systems. Roads were especially bad due to the fact that previously plowed streets became very slick with the glaze of ice on them. Buses were not able to drive off the main roads in Florence and Victor due to the icy roads.

Heavy Snow in FLATHEAD/MISSION VALLEYS, MONTANA
From 04-JAN-15 18:00:00 to 06-JAN-15 04:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Glacier Park International Airport reported 19.2 inches of storm total snowfall which became the 6th highest 2-day snowfall on record. Several families were stranded at their homes until they were plowed out because of the heavy snow. Most schools closed on Jan. 5 and also on Jan. 6 except for portions of the Mission Valley where 2-hour delays were common. The Kalispell City Manager reported that there were some roads that were impassable without 4WD vehicles. Weather spotters reported trees down in Bigfork and also over Highways 35 and 83. Other notable storm total snowfall totals include: 26.5 3 miles north of Bigfork, 23 Woods Bay, 21.5 Bigfork, and 8.5 4.1 miles northeast of Ronan.

Heavy Snow in LOWER CLARK FORK REGION, MONTANA
From 04-JAN-15 19:00:00 to 06-JAN-15 08:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

MDT reported severe driving conditions from Superior to St. Regis and Lookout Pass during the late evening on Jan. 4. They reported that it was so heavy at times that the snow plow drivers couldn't keep up. Chains were required over Evaro Hill for towing vehicles from roughly 5 am to 9 am MST on Jan. 5 which is a rare occurrence. Storm total snowfall at Lookout Pass was 21 inches while Heron saw 17 inches.

Heavy Snow in BITTERROOT / SAPPHIRE MOUNTAINS, MONTANA
From 05-JAN-15 00:00:00 to 06-JAN-15 08:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

The MDT estimated 18 inches of snow fell at Lolo Pass through the morning of Jan. 5. Snow changed to rain by the afternoon and by nightfall road surfaces became slick again. The MDT foreman in charge the Lolo Pass stretch mentioned that a small car would have had a tough time due to the very heavy snowfall rates. A 43-year-old man was killed on Highway 12 west of Lolo when his vehicle hit ice on a curve. Other factors involved included alcohol and not wearing his seat-belt.

Winter Storm in BUTTE / BLACKFOOT REGION, MONTANA
From 05-JAN-15 00:00:00 to 06-JAN-15 08:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

The MDT reported severe driving conditions from 9 pm Jan. 5 through 1 am MST Jan. 6 over MacDonald Pass due to heavy snow. A snow slide occurred near the intersection of Highways 200 and 141 closing one lane of traffic around 1 pm on Jan. 5.

Avalanche in WEST GLACIER REGION, MONTANA
From 05-JAN-15 09:20:00 to 05-JAN-15 09:20:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

The MDT reported that a snow slide affected Highway 83, two miles north of Swan Lake. Except for traffic being diverted to one lane, no further information was provided on the size of the avalanche.

Heavy Snow in KOOTENAI/CABINET REGION, MONTANA
From 05-JAN-15 02:00:00 to 06-JAN-15 06:00:00 (MST-7)
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Department of Highways

The MDT reported that between 11 to 16 inches of snow fell between Marion and Happy's Inn, up to 20 inches between Libby and Happy's Inn on US-2. They reported that the snow changed to freezing rain at times later on Jan. 5 through the early morning hours of Jan. 6. The Lincoln County Emergency Manager reported a few downed power lines and brief power outages. A weather spotter just southwest of Libby measured 18 inches of snow while Troy receive 11 inches.

Winter Storm in WEST GLACIER REGION, MONTANA
From 04-JAN-15 22:00:00 to 06-JAN-15 23:00:00 (MST-7)
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The BNSF avalanche forecaster reported a storm total snowfall in Essex of 20.4 inches with 1.40 inches of snow water equivalent. They reported that the snow changed to freezing rain on Jan. 6 and then the second push of arctic air froze everything up solid. A large avalanche covered US-2 10 miles north of Essex while a second avalanche occurred around 920 am on Jan 5, two miles north of Swan Lake. The West Glacier and West Valley school systems were closed on Jan. 6.  Blowing snow was reported at Bad Rock Canyon and at Marias Pass.

Avalanche in WEST GLACIER REGION, MONTANA
From 06-JAN-15 05:35:00 to 06-JAN-15 05:35:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

The MDT reported an avalanche that blocked both lanes of US-2 located 10 miles west of Essex near the Blue Rock Cut or at milepost 168.6. It was approximately 30 to 40 yards long, 3 feet deep on down hill side, and 5 feet deep on the uphill side. One lane was opened up after 1.5 hours while the other lane took an additional hour to clean up.

Winter Storm in POTOMAC / SEELEY LAKE REGION, MONTANA
From 04-JAN-15 14:00:00 to 06-JAN-15 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A person from the public located one mile south of Condon measured 12 inches of heavy snow that changed to freezing rain by the morning of Jan. 5. They also reported that the power went out starting at 6 pm MST on Jan. 4. At one point Highway 200 east bound lanes east of Bonner were closed for several hours due to a snow slide. MDT also reported severe driving conditions along Highway 200 due to icy conditions and freezing rain. The Seeley-Swan school system was closed on Jan. 6 because of the freezing rain.