Avalanche Forecast

Issued: Feb 26th, 2017 4:33PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada ghelgeson, Avalanche Canada

Changing winds may transport recent storm snow into deep pockets on several aspects.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

While Monday is expected to be a rather benign weather day, significant snowfall is expected to begin early Tuesday, continuing into the foreseeable future as a series of storms roll in from the gulf of Alaska.MONDAY: Overcast skies, freezing level at valley bottom, light to moderate NW wind, no significant precipitation expected. TUESDAY: Overcast skies, freezing level near valley bottom, moderate to strong SW wind, 2 to 15 cm of snow. WEDNESDAY: Overcast skies, freezing level around 500m, moderate to strong SW wind, 2 to 8 cm of snow. Visit avalanche.ca/weather for a more detailed mountain weather forecast.

Avalanche Summary

On Saturday control work produced small size 1 avalanches running up to 10 cm in depth on the February 21st surface hoar interface. Some loose snow sluffing from steep terrain has been reported. Changing wind directions may develop new wind slabs in the alpine. There was a report of a size 2.5 natural avalanche in the northern part of the region. This may have happened in the last 4 days and possibly failed on a persistent weak layer buried early february on a NW aspect in the alpine.

Snowpack Summary

A recent addition of up to 10 cm of new snow has not dramatically changed the snowpack structure, but Saturday night's storm buried a new layer of surface hoar. At this time it is unknown how well preserved this surface hoar is. Recent clear cold weather and shifting winds have created a variety of surface conditions including isolated wind slabs, pockets of soft snow (15 to 25 cm deep), sun crusts, and surface hoar. A supportive rain crust exists below 1000 m. A layer of surface hoar that was buried on February 10th can be found buried 30 to 60 cm deep at tree line elevations and has been reactive in some recent snowpack tests. Below this layer, the snowpack is generally settled and strong. The exception is shallow snowpack areas around Bear Pass and Ningunsaw where basal facets remain an ongoing concern.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs likely exist on a variety of aspects, including fresh wind slabs formed by outflow winds and lingering wind slabs from last week's storm.
Use caution above cliffs where small avalanches may have severe consequences.Use ridges or ribs to avoid pockets of wind loaded snow.Be alert to conditions that change with elevation.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 27th, 2017 2:00PM