After an unusually warm November, this event was a large change to cold and wintry conditions for travelers and hunters alike. A warm front followed by a cold front brought periods of heavy snow that caused slick driving conditions to western Montana. Cold temperatures developed at the end of the event contributing to solidifying moisture on the roads and slick roads for the morning commute on Dec. 5th.

Winter Storm in BITTERROOT / SAPPHIRE MOUNTAINS, MONTANA
From 04-DEC-16 00:00:00 to 05-DEC-16 08:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Lost Trail Pass received 8 inches of snow while Lolo Pass saw 13 inches of snow during this event. A strong cold front moved through between the afternoon and evening of Dec. 4th which initiated gusty winds and temperatures dropping into the teens at Lolo Pass and single digits at Lost Trail. The combination of fresh snow, dropping temperatures and wind chills approaching 15 degrees below zero caused dangerous conditions in the back-country for hunters.

Winter Storm in LOWER CLARK FORK REGION, MONTANA
From 04-DEC-16 00:00:00 to 05-DEC-16 07:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Moderate to heavy snow contributed to severe driving conditions along Interstate 90 by the afternoon of Dec. 4th which continued through the nighttime hours. Lookout Pass received 16 inches with this storm. Gusty winds and falling temperatures into the teens and single digits after the cold front passage contributed to hazardous conditions in the back-country.

Winter Storm in KOOTENAI/CABINET REGION, MONTANA
From 03-DEC-16 18:00:00 to 05-DEC-16 08:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Moderate to heavy snow fell in the valleys and mountains during this event: 21 inches at Stahl Peak at 6000 feet east of Eureka, 12 inches north of Kila at 4000 feet, up to 12 inches in the Eureka area and 4 to 10 inches in other valley locations. Temperatures plummeted to the teens and single digits in the mountains with gusty winds to 35 mph which created dangerous conditions for back-country users.

Heavy Snow in WEST GLACIER REGION, MONTANA
From 04-DEC-16 02:00:00 to 04-DEC-16 22:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter located near the Blankenship Bridge between West Glacier and Columbia Falls reported near whiteout conditions from heavy snow.  A business in Essex reported that 18 inches of snow had fallen with the storm.

Winter Weather in MISSOULA / BITTERROOT VALLEYS, MONTANA
From 04-DEC-16 18:00:00 to 05-DEC-16 02:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Road conditions became slick as snow melted and then refroze during the evening of Dec. 4th continuing into the following morning. The South Hills, including the Miller Creek area of Missoula, saw several slide-offs and accidents due to the slippery roads. This resulted in the local police stating that emergency travel only was advised around 10 pm on the 4th.

Winter Storm in POTOMAC / SEELEY LAKE REGION, MONTANA
From 03-DEC-16 22:00:00 to 05-DEC-16 07:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Periods of light to heavy snow fell during this event. A few places did mix with rain in the afternoon of Dec. 4th. While over a foot of snow fell in the mountains, Lindbergh Lake saw 11.6 inches and Seeley Lake saw 3.7 inches of total snowfall. Once the cold front passed through later Sunday, temperatures fell into the teens by Monday morning causing slick spots on the roads. The combination of fresh snow and cold temperatures created dangerous conditions in the back-country.

Winter Weather in BUTTE / BLACKFOOT REGION, MONTANA
From 04-DEC-16 17:00:00 to 05-DEC-16 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

A person from the public tweeted that Interstate 90 eastbound of mile marker 145 was snow and ice covered at 9 am on Dec. 5th. Light snow fell during the evening of Dec. 4th with the cold front passage and temperatures fell into the teens and 20's making road mitigation difficult.

Heavy Snow in FLATHEAD/MISSION VALLEYS, MONTANA
From 04-DEC-16 12:00:00 to 05-DEC-16 09:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several heavy snow bands, with snow rates up to 5 inch per hour, developed during the day of Dec. 4th then a weak Arctic cold front tracked south during the evening causing widespread snow. As this front lost its steam towards Flathead Lake a heavy snow band formed and impacted much of Highway 35 towards the northeastern Mission Valley. Above freezing temperatures during the day contributed to a snow-over-ice situation by the evening, and very slick conditions lasted into the next morning. Total snowfall amounts include: 9 Columbia Falls, 5.5 Bigfork, 4.6 Glacier Park International Airport.