Avalanche Forecast

Issued: Jan 19th, 2018 4:00PM

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

william lawson, Parks Canada

Little Yoho.

There is still lots of uncertainty on how the surface hoar at treeline will react, make conservative terrain choices at this elevation and take the time to look in the snowpack for this problem.

Summary

Weather Forecast

Trace amount of snow forecasted for Saturday, a small system is expected for Sunday evening bringing in 5-10cm on snow by Monday. Winds will remain in the light to moderate range through the weekend and temperatures steady between -12 to -14 at treeline.

Snowpack Summary

Recent winds have developed windslabs on alpine and treelin lee slopes. In sheltered areas the upper snowpack has 20-30cm of soft slab over the Jan 6 surface hoar, this layer has been reactive in test results. The Dec 15 surface hoar layer is still a concern in the region, in many areas this layer is 50-80 cm down with a settled slab above.

Avalanche Summary

No new avalanche activity reported in this forecast region.

Confidence

Problems

Wind Slabs

Recent snow and wind are have created new windslabs on lee slopes at alpine and treeline elevations. Due to variable winds in the alpine expect the spacial distribution of this problem to be widespread.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

The dec 15 layer is a concern mainly at treeline around Field, Emerald Lake and Little Yoho - this is a very specific band. Watch for overhead hazard BTL; avalanches can run into the forest.

Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Jan 20th, 2018 4:00PM