Avalanche Forecast

Moderate - Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.

We’re entering a rather quiet weather period with coolish temps and no significant snowfall expected, at least through boxing day. The region should see winds pick up later in the week and there is potential for a small shot of snow Thursday night.

CHRISTMAS EVE: Freezing level at valley bottom, light variable wind, no significant precipitation expected.

CHRISTMAS: Scattered cloud cover, freezing level near valley bottom, light northwest wind, no significant precipitation expected.

BOXING DAY: A few clouds in the morning building to overcast by sundown, freezing level at valley bottom, moderate to strong west/southwest wind, trace of snow possible during the day, potential for 1 to 5 cm by Friday morning.

FRIDAY: Broken cloud cover at dawn with potential for some clearing in the afternoon, freezing level at valley bottom, moderate to strong west/northwest wind, trace of snow possible during the day.

A deep persistent weak layer in the snowpack has been responsible for some very large and destructive recent avalanches. The potential for very large avalanches still exists in the region.

On Monday control work produced very large (size 2.5 to 3.5) avalanches on a variety of aspects in the alpine. Some of these avalanches ran beyond historical norms and created new trim lines where there were once trees.

On Sunday, there were numerous reports of natural and human triggered avalanches size 2-2.5 and explosives triggered avalanches up to size 4. A number of these avalanches were reported to have run on the deep persistent weak layer near the base of the snowpack.

Avalanche activity was widespread on Friday and Saturday with reports of natural, human and explosives triggered avalanches up to size 3.

The Purcells received 60-120 cm of new snow since Thursday night. Storm slabs are likely widespread and are expected to continue to be reactive to human triggers.

There may be two layers of surface hoar buried between 70-180 cm. These layers likely exists mostly in sheltered areas at treeline and may be reactive to human triggers.

The base of the snowpack is generally quite weak and consists of a crust, facets and depth hoar. This deeper weakness in the snowpack has been responsible for numerous recent avalanches and remains a major concern in the region.

• Stick to simple terrain and be aware of what is above you at all times.
• Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.
• Avoid the runout zones of avalanche paths. Avalanches could run full path.