Nov 25, 2015 @ 8:33 am

Hi everyone, this is Steve Karkanen at the West Central Montana Avalanche Center with early season avalanche safety information issued Wednesday, November 25, 2015.

A robust Canadian cold front passed through the area yesterday bringing snow, high winds and colder temperatures. Most SNOTEL stations report around 5 inches of new snow and single digit temperatures. The Point Six RAWS station is reporting winds in the 30’s w/ gusts to 48mph. The wind chill this morning is -25f .  The area remains under a winter storm warning until 10am.

High winds the past 24 hours started out from the east but are now more westerly. We normally expect wind slabs on the lee east facing terrain but expect to see them on ANY lee slope above treeline after this recent storm. These fresh wind slabs can be touchy for a few days and are the primary avalanche problem in the higher terrain.

In past years there have been a number of early season close calls and fatalities in Montana involving hunters and climbers. Hunters tend to travel solo without avalanche rescue equipment as avalanches are about the last thing they are thinking of as they follow elk tracks across steep, open terrain.

If you see any of these obvious clues to dangerous snow conditions, avoid being on or under open slopes steeper than 30 degrees.

  • recent avalanche activity –
  • cracking or collapsing snowpack
  • heavy snowfall
  • high winds
  • rapid increase in temperature

If you spend any amount of time in the mountains in the winter, chances are good that you will encounter avalanche terrain. Having basic awareness of terrain, weather and snow factors goes a long way toward making good decisions in avalanche terrain. To that end we are offering several basic and advanced avalanche awareness classes this winter. We also have instructors available to give your organization a range of programs from introductory to classes with a field component. Check out our course offerings here:

We are also offering a Level 2 in partnership w/ the American Avalanche Institute. Details are available here. You must register w/ AAI prior to December 19.  The class will be cancelled if there are not enough participants.

We plan to begin issuing regular avalanche advisories w/ the danger rating in mid-December.

We’ve been getting some good reports and have a few posted on our public observations page. Any information you send is appreciated and helps inform the rest of the community about avalanche safety conditions. You can send a quick email to [email protected] or use the easy to use form here:


Problem 1 - Fresh Wind Slab

  • TYPE


    Wind Slabs

    Release of a cohesive layer of snow (a slab) formed by the wind.  Wind typically erodes snow from the upwind sides of terrain features and deposits snow on the downwind side.  Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

  • SIZE


    1 (Small)

    The potential size of avalanche resulting from this problem.




    The likelihood of an avalanche resulting from this problem.


    Increased Slope Danger

    Increased/Added Danger

    There is an increased risk of avalanches on these slopes:

    NE - Northeast
    E - East

High winds the past 24 hours have been mostly from the east.  We normally expect wind slabs on the lee east facing terrain but expect to see them on ANY lee slope above treeline after this recent storm. These fresh wind slabs can be touchy for a few days.


A Canadian front continues to slide south along the Divide bringing high winds and very cold temperatures to western Montana. The Missoula Office of the National Weather Service is forecasting high winds and blowing snow through Wednesday then single digit temperatures w/sub-zero wind chills in some valley locations on Thanksgiving and Friday.  The air mass is expected to be mostly dry through the weekend into mid-week.

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.