Avalanche Forecast

Issued: Jan 27th, 2016 8:35AM

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

jlammers, Avalanche Canada

South Coast.

Touchy conditions still exist in many parts of the region. A warm, wet and windy storm will cause conditions to deteriorate.

Summary

Confidence

Moderate - Track of incoming weather systems is uncertain on Thursday

Weather Forecast

15-20mm of precipitation is forecast for Wednesday night with another 15-20cm of snow expected on Thursday. Ridgetop winds will remain extreme from the southwest while freezing levels will drop throughout the day from 2000m to about 1500m. On Friday and Saturday the region will see generally light flurries, significantly decreased winds and freezing levels around 1000m.

Avalanche Summary

In recent days, backcountry avalanche observations have been extremely limited, mostly due to stormy weather. That said, I suspect persistent weaknesses have remained sensitive to human triggering, especially in the north of the region where very touchy conditions were reported to persist. Looking forward, continued warm, wet and windy weather is expected to spark ongoing storm slab activity in high elevation lee terrain, but warm temperatures and loading will also increase the likelihood of waking up any lingering persistent weaknesses that were not triggered by last week's storm.

Snowpack Summary

On Wednesday and Thursday, moderate snowfall and strong winds will continue to form deep and dense storm slabs in high elevation terrain and cause substantial cornice growth. At lower elevations rain is forecast to further saturate the upper snowpack. In some areas, last week's storm and the resulting avalanche cycle helped flush-out the mid and early-January surface hoar/facet layers now down 60-120 cm deep. However, these layers are still intact and reactive in many places and it may still be possible to trigger large slabs. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted.

Problems

Persistent Slabs

Buried surface hoar remains primed for rider triggering in many areas, especially in the Northern part of the region. Forecast rain and wet snow will increase the likelihood of avalanches failing on this touchy weak layer.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Be wary of slopes that did not previously avalanche - even on low angle terrain.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Wind Slabs

Continued precipitation, warm temperatures and wind on Wednesday will form dense new wind slabs in high elevation lee terrain. At lower elevations where rain is expected, loose wet avalanches are also possible.

Choose well supported terrain without convexities.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 28th, 2016 2:00PM