Mar 21, 2014 @ 6:08 am

Avalanche Advisory for March 21, 2014

The avalanche danger is MODERATE in the west central Montana backcountry.

Natural avalanches are unlikely but human triggered avalanches are possible. Heightened avalanche conditions exist on steep, recently wind loaded terrain at the higher elevations.

Carefully evaluate snow, weather and terrain as conditions can change dramatically over short periods of time and distance.

Hello!  This is Steve Karkanen at the West Central Montana Avalanche Center with the avalanche advisory for Friday, March 21.  The avalanche danger rating expires at midnight tonight and does not apply to operating ski areas.

Snow and Weather

Since Tuesday, SNOTEL sites have picked up an average of .50″ of SWE or about 5″ new snow with temperatures staying cool. This morning, mountain temperatures are in the teens and winds have calmed with both the Point Six and Deer Mountain RAWS stations reporting west winds at 9 mph.

The primary avalanche problem in the west central Montana backcountry is wind slab formation on any lee terrain steeper than 35 degrees. These wind slabs are being reported on multiple aspects and in areas further down slope that have been cross loaded by high winds earlier this week.

A secondary problem is loose snow sloughing off the hard old snow surface on steeper terrain.

Cornices are huge and can’t be trusted. They have a nasty habit of breaking farther back than expected so give them a wide berth.

Yesterday, Ed and Casey were in the southern Bitterroot near Lost Trail and they report mostly stable conditions with wind slabs and cornices being the main concerns.

We received a  report from Blake at Downing Mountain Lodge Wednesday who gave a great description of the wind slab problem on some of the terrain in the Central Bitterroot earlier this week.

Tim and Dave rode into the Brushy Fork area on the MT/ID line and were able to tour to a site near Rocky point . They also describe conditions as being mostly stable with recent wind slabs and cornices being the primary avalanche problem.

Al and Dan rode out to Hoodoo Pass yesterday and sent a report on conditions there. Like many other western Montana locations, a significant avalanche cycle occurred in this area within the past two weeks. You can view the  photos of the slide path at Gully’s and see the equally impressive amount of total snow in Al’s profile.

In the Rattlesnake, wind gusting to 45 mph from the W-SW was moving snow throughout the day. Travis and Logan reported the main avalanche problem here is wind slab formation mostly on east facing terrain with cross loading on the south aspects. In sheltered areas, new snow on a sun crust was reactive and will easily slough on steeper slopes. View the Rattlesnake profile here.

Weather and Avalanche Forecast

The National Weather Service Forecast Office in Missoula is tracking an arctic air mass that will impact much of western Montana this weekend. The main impact will be north and east of our advisory area but we can expect colder temperatures and higher winds this weekend. The Seeley Lake area may see as much as 6 inches of new snow by late Saturday with smaller amounts in the Bitterroot mountains.

I don’t expect much change in the overall avalanche danger unless the mountains receive higher snowfall amounts with wind this weekend. Wind slabs are the main issue now and will continue to be a factor for several days.

Mount Jumbo and Altoona Lakes Avalanche Reports.

A preliminary report on the Mount Jumbo avalanche is available for viewing on our Accidents page.  This report will be updated as more information is made available to us.

A report on the Altoona Lakes avalanche is now complete and available for viewing.


If you get out, send an observation to our Public Observations page. You can also send a short email to [email protected]. Your information is helpful and helps people make more informed decisions.

The Draught Works Cheers For Charity event last Tuesday evening was a great success. Thank You!

A special thanks goes out to those who were involved with or who know people who are involved in the Mount Jumbo and Altoona Lakes avalanches.  This has been a tough time and our thoughts are with you.

Dudley will issue the advisory on Tuesday March 25.


This information is the sole responsibility of the Forest Service and does not apply to operating ski areas. The avalanche danger rating expires at midnight tonight but the information can help you make a more informed decision regarding travel in avalanche terrain for the next few days.

Our advisory area includes National Forest System lands in the Bitterroot Mountains from Lost Trail Pass north to Granite Pass, the Rattlesnake Mountains north of Missoula and the Southern Swan and Mission Mountains near Seeley Lake, MT. Avalanche information for the Lookout Pass/St. Regis Basin area is available from the Idaho Panhandle Avalanche Center.