Avalanche Forecast

Issued: Nov 29th, 2018 5:09PM

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

jsmith, Avalanche Canada

Cariboos.

There is a lot of uncertainty with the reactivity of the buried surface hoar layer down 40-80 cm. Human triggered avalanches are more likely at treeline and sheltered locations in the alpine where this weak layer exists. New Forecaster blog HERE.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

Overnight THURSDAY: Cloudy with isolated flurries / Alpine Low -8 / Light, west wind / Freezing level valley bottom.FRIDAY: Mostly cloudy / Alpine high -6 / Light, southeast wind / Freezing level valley bottom.SATURDAY: Mostly cloudy / Alpine high -6 / Light, northeast wind / Freezing level valley bottom.SUNDAY: Mix of sun and cloud / Alpine high -7 / Light, northwest wind / Freezing level valley bottom.

Avalanche Summary

No avalanches were reported in this region on Wednesday. However, we currently have very few observations from within this region. Please post your observations to the Mountain Information Network. (MIN)

Snowpack Summary

Recent storm snow amounts range from 40-70 cm. This new snow sits on top of a weak layer of surface hoar (feathery crystals) and sun crust on steep south facing slopes. The surface hoar is most pronounced at treeline, but it may be found in sheltered, north facing alpine areas.At the base of the snowpack is a crust that formed in late October. There have been no reports of reactivity on this layer; however, this layer may be reactive to human triggers in isolated locations such as steep, rocky terrain, with a shallow snowpack. Small avalanches may step-down to this crust resulting in large, destructive avalanchesSnowpack depths decrease dramatically with elevation.

Problems

Persistent Slabs

Be especially cautious with this buried weak layer in the Treeline elevation band, on large open slopes that have a deep enough snowpack to bury all the bushes and make the slope smooth. It may also be present in sheltered, N. facing alpine slopes.

Start in conservative terrain while you gather additional information about the snowpack.Watch for signs of instability such as ‘whumphing’, cracking, and evidence of recent avalanches.Use small slopes with no consequence to test for the presence of the buried weak layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 30th, 2018 2:00PM