Mar 18, 2014 @ 6:52 am

Avalanche Advisory for March 18, 2014

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

Natural avalanches are unlikely, human triggered avalanches are possible.

It will be possible to trigger an avalanche on recently wind loaded slopes steeper than 35 degrees near ridges.

Cornices are sensitive now and can’t be trusted. It is also possible to trigger a much larger avalanche in shallow rocky terrain where weak snow exists at the bottom of the snowpack.

Good morning!  This is Steve Karkanen with the Tuesday backcountry avalanche advisory provided by the West Central Montana Avalanche Center.  The avalanche danger rating expires tonight at midnight. This information is the responsibility of the Forest Service and does not apply to operating ski areas.

Special Announcement:

A celebration of Peter Maxwell’s life is being held at 4 pm today at Caras Park in downtown Missoula.   Our thoughts and prayers are with Peter’s family and friends during this difficult time.

Weather And Snowpack

A quick moving storm passed through western Montana Monday dropping several inches of snow in most mountain locations.  SNOTEL sites recorded 6-10 inches of new snow in the past 24 hours. This morning, mountain temperatures are in the 20’s and northerly winds are 27 mph at Point Six and 12 mph at the Deer Mountain RAWS station at 7200 feet near Darby, MT.

Travis and Dudley toured an area near Lolo Pass yesterday and found fair stability conditions (view profile) with wind loading being their primary concern. They also indicated that wet slab avalanche activity will become a problem during warm, sunny days or if it rains.

The primary avalanche problem today is wind slab formation in areas where high winds pummeled the ridges. Wind speeds during the storm yesterday were in the 30-40 mph range. Snow plumes were seen in the Bitterroot peaks Sunday and Monday so any available snow was obviously getting moved around.

A secondary avalanche problem, very much related to the first, is the cornice build up of the past few weeks.  We’ve seen and have received reports of cornice collapse triggering avalanches in the Bitterroot and Rattlesnake recently.

These 2 creatures of the wind deserve the same level of respect a Grizzly bear commands.  Similar to the great bear, cornices and fresh wind loaded terrain are an awesome sight, but you don’t want to get to close to, or jump on one. Give these features a wide berth especially during warm sunny weather.

The weather of the past few days has been exactly what is expected for mid-March in the northern Rockies. The best powder skiing of the winter can be in March but you must be quick and hope the sun stays hidden by cloud cover.  As soon as the sun hits any slope, the snow turns to glop and wants to start moving to the Pacific Ocean.

On warm days, pay close attention to how the sun is affecting stability. Visual clues such as pinwheels and small point release avalanches are indicators of changing stability. Move onto more shaded terrain and avoid being on or under steep open terrain.

Weather and Avalanche Forecast

The Missoula Weather Service is forecasting scattered mountain snow showers to persist today with a strong weather disturbance expected to enter the area Wednesday and Thursday. Up to 6 inches of new snow is expected with this system. Additional new snowfall and wind will increase the avalanche danger to CONSIDERABLE on wind loaded terrain.  Clear skies will rapidly raise the avalanche danger on any steep sun exposed slope steeper than 35 degrees.

Benefit for Missoulaavalanche

The past 2 weeks have been an exceptional challenge for us. We have been involved with the Mount Jumbo and more recently the Altoona Lakes avalanche investigations. Both are outside our advisory areas and in both cases, the responsible agencies asked for our assistance.

The Mount Jumbo avalanche was a rare event, but one that required an unusual amount of involvement from us.  An on-going avalanche hazard to a residential area required our daily attention, which we responded to.

We will continue to assist the City, and other agencies, with avalanche hazard assessment when the need arises. Our ability to do this is highly dependent on the support we receive from you.

We receive NO direct financial assistance from the Forest Service, which is our host agency. 100% of our operating budget comes from donations to the non-profit, West Central Montana Avalanche Foundation.

Please consider a tax-deductible donation to this organization.

Tonight, at 5-8pm, Draught Works, 915 Toole Street, is sponsoring a Cheers for Charity event for the West Central Montana Avalanche Foundation. A portion of the proceeds from this event will go directly back into the community in the form of avalanche advisories and avalanche classes.  Hope to see you there!

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.

I will issue the next advisory this Friday, March 21.  Please be safe out there!


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.