Winter Storm and Extreme Cold in Montana, March 1 to 3, 2019

Severe driving conditions were reported for MT-83 between Condon and Ferndale due to blowing and drifting snow. While only a trace of snow feel between West Glacier and Marias Pass, bitterly cold temperatures followed the arctic cold front passage in those areas. Other snow amounts ranged from 4.5 inches near Swan Lake to 8 inches at the Hungry Horse Dam.

Emergency Travel Only, was issued for Lake County due to blowing and drifting snow with low visibility. Numerous accidents and slide-offs caused tow service to be backed up as much as three hours during the event in the Flathead Valley. While new snowfall ranged from two to four inches with up to 5.8 inches in Whitefish, the main cause of the high impact was more due to the combination of existing one to two feet of snow on the ground with strong winds sustained between 20 and 33 mph with gusts over 40 mph. The GPI airport recorded a peak wind speed of 43 mph at 7:41 pm on March 1.

Because of sub-zero ambient temperatures and wind chill temperatures, Blacktail Ski Resort closed on March 2. Snow amounts ranged from 2 inches in Eureka to 5.3 inches in Marion. The Boorman RAWS weather sensor near Marion saw wind gusts between 20 and 30 mph at times Friday evening March 1 through early morning Saturday which caused blowing and drifting snow with low visibility along US-2.

Around 9 pm on March 1, the Missoula County sheriff department issued a MEANS 911 alert for Emergency Travel Only from Interstate 90 at Hellgate Canyon to Revenna just west of Bearmouth. They stated that there were multiple accidents due to white-out conditions. Between 20 to 30 inches of snow were already on the ground before the strong arctic winds pushed through causing the blowing and drifting snow.

Severe driving conditions were reported in two separate areas, along Highway 141 between Helmville and Highway 200, and on Interstate 90 between Phospate and Deer Lodge due to slick roads and poor visibility from blowing and drifting snow.

Though minimal new snowfall amounts only ranged from a trace up to 1 inch, pre-existing transportable snow on the ground combined with strong wind gusts in constricted areas such as eastern Thompson Falls, generated blowing and drifting snow for a period. The Thompson Falls airport had a peak wind of 42 mph around midnight March 2.

Poor visibility due to heavy snow bands was followed by blowing and drifting snow caused by strong arctic easterly winds. At 9 pm, a MEANS alert was issued by the Missoula County sheriff's office to tell the public about poor driving conditions. Around midnight, Severe Driving was declared by the Montana Department of Transportation between Lolo and Missoula due to poor visibility from blowing snow and drifting on US-93. Snow drifts, approximately several feet in depth, were reported from the Rattlesnake, Missoula and Lolo locations. While new snowfall amounts between a half an inch at the Missoula Airport up to 5 inches in Lolo were observed, the antecedent transportable snow on the ground contributed to most of the low visibility and heavy drifting during this event. By the evening of March 2, wind chill temperatures ranged between 10 and 20 below zero.

A NWS employee located in Lolo reported 5 inches of snow that fell in only 3 hours under the snow band that also affected Highway 12 west to Lolo Pass.

A Montana Department of Transportation weather sensor in Essex reported air temperatures of 10 to 20 below zero with sustained winds of 10 to 20 mph which produced wind chill values between 30 and 48 degrees below zero.

Bitterly cold wind chill temperatures between 25 and 30 below zero were measured at Garrison Junction and Elliston and as cold as 40 below zero at both MacDonald Pass and Anaconda.

Wind chill values between 20 and 28 below zero were reported by the Glacier Park International Airport ASOS during this event.