Avalanche Forecast

Issued: Jan 15th, 2013 8:06AM

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

Sylvia Forest, Parks Canada

Glacier.

Watch for solar warming in the alpine, especially on sunny slopes. Moderate winds continue to create wind slabs and cornices. Pay attention to changing conditions today!

Summary

Weather Forecast

A ridge of high pressure will maintain dry conditions today, however a NW flow may spread some cloud and snow later today and Wednesday. An inversion is also likely today. The inversion, combined with sunny breaks and solar radiation, may cause snow to become weak and unstable on solar aspects,

Snowpack Summary

Soft and hard wind slabs overlie the January 4 sun crust-surface hoar layer. This layer is down 40-60cm. The sensitivity of this layer is quite variable, however skiers have been triggering avalanches on this layer in specific terrain features. Steep solar aspects are most reactive. The mid-pack remains strong.

Avalanche Summary

Skiers have been triggering avalanches in isolated locations in the alpine and treeline, mostly on steep solar aspects. The largest of these was a size 2.5 Sa from two days ago, and a size 1.5 from Grizzly Shoulder yesterday. Isolated natural avalanches have been observed from steep start zones. Use caution on wind loaded areas on solar aspects.

Confidence

Timing or intensity of solar radiation is uncertain on Wednesday

Problems

Persistent Slabs

A cohesive slab overlies the January 4 persistent weak layer. Variable distribution and composition makes this layer difficult to predict. It is most reactive on steep solar aspects. There have been two skier triggered slides on this layer.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Upper level winds from the N have created wind slabs on S-SE slopes in the alpine. Winds around 2000m are from the south, loading N-NE slopes. Watch for windslabs in the alpine; if triggered they may step down to the persistent slab.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 16th, 2013 8:00AM