West of the Continental Divide: 

Below: Chair 1 base at Whitefish under heavy snow Wednesday morning.

 

Quite a bit has changed since my last post on Monday with the further deepening of an impressive longwave low-pressure trough over the PNW. This trough has begun to move south Wednesday morning drawing a moist southwest (SW) flow which is merging with arctic air at the surface to bring periods of heavy snowfall to the region. Waves of moisture will be moving through this active SW flow with off-and-on periods of snowfall likely through Thursday night. 

While the mountains of Idaho lie in the bullseye of the storm, the Bitterroots and Purcell mountain ranges along the Idaho/NW Montana border (Lookout Pass, Turner Mountain) as well as the mountains in the vicinity of Glacier NP (Whitefish) look to receive the deepest storm totals in the neighborhood of 10” – 17” by Friday morning. 

Elsewhere, Snowbowl and Lost Trail are also in a good place for up to 10” through Friday. Slightly lesser amounts in the 4 – 6” range are anticipated at Discovery and Blacktail. Temps will continue well below seasonal averages, so the dendrite growth looks to be enhanced up to 15:1 (15” snow to 1” liquid precip).     

For Friday, snow showers continue across the region generally ending before noon. Another 1 – 3” are possible under heavier snow showers. Saturday looks benign with a mix of sun and clouds with continued below average temps. On Sunday clouds will be on the increase ahead of our next storm system expected to arrive overnight on Sunday. Light accumulations in the 1 – 3” range are probable by Monday morning.

East of the Continental Divide:

A deep trough will dig south from the BC coast into the Inter-Mountain West over the next 24-36 hours creating a SW flow of Pacific moisture that will ride over the arctic airmass east of the Divide. What this means is various waves of snowfall are likely through Friday afternoon with moderate to heavy accumulations. The mountains of far SW Montana near West Yellowstone will get dumped on with around 16”. Big Sky lies just north of this moist flow, but still looks in good shape for 6” - 10” by Friday evening.  

High-resolution weather models are also depicting heavy snow in a line from the Rocky Mountain Front over to the Little Belt Mountains of North/Central Montana where Teton Pass ski area and Showdown are likely to see heavy snow with 7 – 9” storm totals through Friday. Bridger Bowl, Great Divide, and Red Lodge fall in between the heavier bands of moisture, thus lighter snowfall waves will likely bring in 4 – 6” of cumulative snowfall. 

A weak high-pressure ridge will create a westerly flow aloft on Saturday and Sunday drying things out for the weekend. Partly sunny skies are likely for most of the mountain areas and resorts on both days with high temps in the upper teens to low 20’s at 8000’. As another trough of Pacific low-pressure begins its journey eastward on Sunday, look for increasing clouds Sunday night with numerous snow showers with a 50% chance of 1 – 2” by Monday morning. This storm is trending much weaker than previous model runs. 

Below: Canadian high-resolution model for snowfall from Weds afternoon - Friday afternoon. 

 

West and East of the Continental Divide:

Weather models are deviating a bit for the period Monday 12/5 through Friday 12/9. A trough is still favored to move into the Northern Rockies Monday and Tuesday, but the timing and strength of incoming storm systems are still in question. The best scenario is weak storms with possibilities of 1 – 3” inches possible for Monday and Tuesday. Temps are favored by most of the models to stay below seasonal averages keeping our above-average snowpack in check.  

Wednesday and beyond is still a mystery but likely continued cold.     

Below: CPC’s 8-14 day favors continued below average temps with slightly above average precipitation for NW Montana.

 

 Thanks for tuning in, next update is on Thursday 12/1. 

Powder Out –

 Bob

OPENING Dates - Montana Ski Areas & Resorts / Geographical References   

WEST of the Divide: 

Whitefish Mountain Resort – Closed, Opening Thursday, Dec 8th

Blacktail Mountain –Closed, Opening TBA

Turner Mountain – Closed, Opening TBA

Lookout Pass (MT/ID)  - OPEN Nov. 28, closed midweek, REOPENS Dec 2nd

Montana Snowbowl – Closed, Opening Dec 10th

Discovery Basin – OPEN WEEKENDS ONLY    

Lost Trail Powder Mountain –OPENING Thurs DEC 1^st (Thurs – Sun)     

EAST of the Divide:

Big Sky Resort – OPEN daily

Bridger Bowl – Closed, Opening Dec 9th

Red Lodge Mountain – OPEN daily  

Great Divide – REOPENING Dec. 3 – 4^th  

Showdown – REOPENING – Dec. 3 – 4^th

Teton Pass Ski Area –Closed, Opening Dec 9th

Maverick Mountain – Closed, Opening TBA 

 

Backcountry Avalanche Reports:

West Central Montana Avalanche Center

http://missoulaavalanche.org 

 Flathead Avalanche Center

 http://www.flatheadavalanche.org

Gallatin National Forest Avalanche Center:

http://www.mtavalanche.com

 

 Estimated Snow Reports

If ski resort locations are closed or do not provide OpenSnow with an official snow report, we use our proprietary weather data to provide an estimated snow report for the past 24 hours. Check for the "Estimated" badge on the OpenSnow app and website.

This also applies to any backcountry location or "custom location", meaning that you can get an idea of recent snow conditions and an estimated snowfall history for your favorite backcountry spots.

This data is available exclusively to All-Access subscribers. Snow reports that are provided to OpenSnow from the ski resorts will always be free.