Posted:
Mar 31, 2018 @ 6:15 am

The avalanche danger is MODERATE for the West Central Montana backcountry. Avalanches are a possibility in specific terrain. Carefully evaluate terrain and snowpack to identify areas of heightened concern.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Saturday, March 31st, 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

The weather is variable across the region. The northern portion of the advisory area has temperatures in the mid to upper twenties, and the wind has shifted to the East. At Point Six wind speeds are 15 mph gusting to 25 mph from the ESE. Minimal snow accumulations for most locations except the Southern Missions where 7 inches have accumulated. The Southern half of the advisory area is still experiencing westerly winds at 9 mph gusting to 23 mph, and temperatures are just above freezing.

Travis and I rode up Wisherd ridge yesterday. Winds continued to be strong, and snow was still available for transport. Wind slabs  have gained strength since earlier this week but are suspect especially in locations where they are sitting on a crust.

Wind slabs continue to be the primary concern. Wind slabs are isolated and vary in size. It is still possible to trigger wind slabs in specific terrain. Look for signs of wind loading and dig a pit to see if the snow is on a slick crust that acts as a great bedsurface for the snow to slide on.

Springtime makes conditions dynamic. You may find yourself in a full-on snow storm or warm sunny conditions at any time. Carefully evaluate conditions as they change through the day and adjust travel plans and objectives accordingly.

Avalanche and Weather Outlook

Continued scattered snow showers will prevent the avalanche danger from changing much today. Snow showers will settle out later in the day today and through tomorrow before another round of moisture sets up again for Sunday.

This is the final scheduled advisory for the season; we will post updates through the spring as conditions warrant. The entire staff at the WCMAC would like to thank everyone who makes this program possible. We had another great season and hope that you did too. Thanks!

If you are out in the backcountry, please send us your observations, we will continue to post them to the site this spring as we receive them.

Ski and ride safe.

READ FULL ADVISORY  

Problem 1 - Wind Slabs

  • 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

    3-4

    1-2 (Small-Large)

    The potential size of avalanche resulting from this problem.

  • LIKELIHOOD

    Likelihood-3

    Possible

    The likelihood of an avalanche resulting from this problem.

Wind Slabs are possible in specific terrain.

VIDEO

03/30/2018

03/30/2018

FORECAST & OUTLOOK

Isolated light snow showers are forecasted today with continued wind.

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.