Avalanche Forecast

Issued: Dec 14th, 2015 9:06AM

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

jlammers, Avalanche Canada

Sea To Sky.

This bulletin was published using limited data from the Garibaldi South corner of the region. Regional snowpack variability likely exists, so be your own forecaster and make observations continually as you travel.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Light flurries are forecast for Tuesday. A mix of sun and cloud is expected on Wednesday and Thursday morning with light snowfall developing by Thursday evening. Ridgetop winds should remain mainly moderate from the northwest with freezing levels hovering around 500m for all 3 days.

Avalanche Summary

Explosives testing on Sunday produced storm slabs to size 2.5 in high elevation lee terrain. Most of the observed avalanche activity released within the new storm snow.; however, in at least 2 cases slabs released on a buried crust. At the time of publishing, no new avalanches were observed on Monday.

Snowpack Summary

5-10cm of low-density snow overlies 40-50cm of snow from last weekend's storm. These storm accumulations were shifted by strong winds into much deeper deposits in high elevation lee terrain. Below 1800m, there was much less wind effect and therefore less cohesion in the newly formed slab.Below 2200m, a hard rain crust can be found approximately 120cm below the surface. Recent tests suggest an improving bond at this interface. That said, in some areas the crust may remain reactive for some time after weaknesses within the storm snow have strengthened.

Problems

Storm Slabs

Last weekend's storm snow has had a few days to settle and gain strength, and storm slab avalanches have become less likely. That said, human triggering is still possible in steep, unsupported, wind-exposed terrain.

Be alert to conditions that change with elevation.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Recent wind and snow have formed new and potentially unstable cornices. Use extra caution when approaching ridge crests.

Extra caution needed around cornices with current conditions.>Stay well back from cornices.>

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 15th, 2015 2:00PM