Mar 5, 2021 @ 6:25 am

The avalanche danger in the west central Montana backcountry is considerable  this morning rising to High this afternoon. Avoid traveling in avalanche terrain today. Very dangerous avalanche conditions exist.

Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Friday, March 5, 2021. This advisory is sponsored by the Trail Head. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content.

Weather and Snowpack

Mountain temperatures range from 19 to 33 degrees this morning. Winds are expected to be 10 mph gusting into the 20’s out of the SW. Mountain temperatures are expected to rise into the 40’s at higher elevations. Today is the last day of warming before a cold front enters our area tomorrow. The snowpack did not refreeze in the Rattlesnake. In the Bitterroot at higher elevations the snowpack had a light refreeze. Warm temperatures today will create wet snow avalanches. Wet slab avalanches are unpredictable. Over the last 2 days we have reports of large wet slab avalanches in the central Bitterroot and southern Bitterroot. Sawtooth Creek on a South facing slope at 7500 ft. In the central Bitterroot on a South facing slope at 8000 ft. 

There are more problems than I can list today. Wet Slab avalanches, wet loose avalanches, cornices, persistent weak layers, and glide cracks. Wet slab avalanches are very unpredictable and produce large unsurvivable avalanches. Today avoid avalanche terrain. Travel on ridges and enjoy the sunshine. Do not cross under avalanche run out zones. Recent avalanches have all been large and run almost the full path of slides reaching valley floors.

Bottom Line

The amount of avalanche problems today and the unpredictability of wet slab avalanches, glide avalanches and cornice failure combined with our persistent weak layers means , today travel in avalanche terrain is not recommended. Avoid runout zones. Avalanches can run long distances and through mature timber. Give cornices a wide birth on ridges. Avoid glide cracks. Wet avalanche problems are notoriously unpredictable.

Carry a beacon, shovel, and probe. Reassess conditions throughout the day and stay alert for signs of instability.

 Upcoming Education Events

Please visit our education page for an up-to-date list of regional educational events and course offerings. Below are a few select events and opportunities to check out.

Special Announcements

The mountains are busier than ever before, with new and veteran backcountry users enjoying the goods. To celebrate the snowfall and help ensure everyone has the information needed to enjoy the mountains and return home safely, we bring you Loving La Niña! This virtual fundraising event includes two outstanding gear packages and two ways to enter to win. Please click HERE for more information about this exciting event. All proceeds benefit west-central Montana’s avalanche forecasting and education programs. Together, we can save lives and continue creating the most fun, safe, and responsible backcountry community possible. Spread the word, and spread the love for La Niña!

Public Observations

Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions.

You can now text us your observations to (406) 219-5566 when you don’t have time to fill out the observations page. Texted observations won’t get posted on the website, but will be used in the development of the forecast.

Ski and ride safe.


Problem 1 - Wet Snow

  • TYPE


    Wet Slabs

    Release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet slabs can be very destructive.

  • SIZE


    3 (Large-Very Large)

    The potential size of avalanche resulting from this problem.



    Likely/Very Likely

    The likelihood of an avalanche resulting from this problem.

Wet slab avalanches are unpredictable. Over the last 2 days warming temperatures have produced large wet slab avalanches. Avoid traveling in avalanche terrain and below run out zones today.

Cornices are large and fail unpredictably. Avoid traveling on slopes with cornices above you.

Problem 2 - Persistent Weak Layers

  • TYPE


    Persistent Slabs

    Release of a cohesive layer of soft to hard snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks.  Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Persistent, Deep-Slab.

  • SIZE


    2-3 (Large)

    The potential size of avalanche resulting from this problem.




    The likelihood of an avalanche resulting from this problem.

Mid elevations and areas that are shallow have weak faceted snow as the base. These have been collapsing under the weight of skiers and we are seeing propagation in tests. It is possible to trigger these deeper layers. Shallower avalanches or cornice fall may step down to these deep persistent layers causing large destructive slides.


Sun and temperatures in the 40’s. Look for a cold front on Saturday. See the forecast.

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.