Posted:
Dec 8, 2018 @ 6:17 am

The current avalanche danger is LOW  across the West Central Montana backcountry. Generally safe avalanche conditions can be found, but careful evaluation of terrain and conditions are still essential for safe travel. Watch for unstable snow on isolated terrain.

Good morning, this is Logan with the West Central Montana Avalanche Center’s avalanche advisory for Saturday  December 08th, 2018.  This danger rating does not apply to operating ski areas, expires at midnight tonight and is the sole responsibility of the U.S. Forest Service.

Weather and Snowpack

As of 5 am this morning mountain temperatures range from the high teens to low twenties. Little snow has been seen for a prolonged period with the occasional dusting of snow. Ridge top winds at Point 6 this morning are at 12 mph gusting to 17 mph from the West.

Currently the primary avalanche concern is wind drifted snow that is creating thin shallow wind slabs. The wind slabs are small but can be serious if you are in the wrong place at the wrong time. Consider the consequences of avalanches before committing to avalanche terrain and follow your safe travel protocols.

The secondary concern are persistent weak layers. These layers are not currently reactive as they generally lack slabs to transfer the energy and propagate, but will be a nagging concern once snow returns to the region. Take note of where you are seeing more surface hoar growth and increased faceting as these will become the problem areas when snow returns.

Avalanche and Weather Outlook

Cold and dry looks to be the norm over the weekend as a high lingers around the region. Inversions have set up with slightly warmer temperatures and clear skies at upper elevations. According to the forecast the next chance for snow looks to be early next week with the potential for a more significant shift by midweek.

If you do make it out into the hills feel free to share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

The next advisory will be issued on Tuesday the 11th.

Ski and ride safe.

READ FULL ADVISORY  

Problem 1 - Wind Drifted Snow

  • TYPE

    wind-slabs

    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

    2-3

    1 (Small)

    The potential size of avalanche resulting from this problem.

  • LIKELIHOOD

    Likelihood-1

    Unlikely

    The likelihood of an avalanche resulting from this problem.

Thin and shallow pockets of wind loaded snow at upper elevations are the main concern.

VIDEO

12/07/2018 Observations

FORECAST & OUTLOOK

Cold and clear will continue to be the dominant feature over the weekend with some temperature inversions. The full National Weather Service forecast can be found here.

 

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.