Avalanche Forecast

Issued: Jan 25th, 2016 9:39AM

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

jlammers, Avalanche Canada

South Coast.

Touchy conditions still exist in many parts of the region. Check out the great Mountain Information Network posts for more details.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

Between 5 and 20cm of new snow is expected on on Tuesday. Areas to the south should see the highest accumulations. Winds will be strong and southwesterly with freezing levels at about 1700m. On Wednesday 20cm of wet snow is expected with strong southwest winds and freezing levels hovering at about 2200m. On Thursday, an additional 10-15cm od snow is expected with moderate southwest winds and freezing levels at about 2100m.

Avalanche Summary

Improved visibility on Saturday gave us a better picture of the extent of the avalanche cycle on Thursday and Friday. Most observers reported very widespread activity with numerous slab avalanches up to size 3 from all aspects and at all elevations. The common theme was that many slides showed very wide propagation, and quite a few released on surprisingly low angle slopes (25-35 degrees). More recently, a skier triggered size 2 persistent slab avalanche was observed in the north of the region around Birkenhead Lake. Check out the great Mountain Information Network posts that detail the touchy conditions in this area.

Snowpack Summary

This weeks "Pineapple Express Light" brought an average of 60-70 cm of new snow to the region. The snow line may have gone up to ridge top in the south, but only 1400-1600 m in the north. Expect dense new wind and storm slabs, and fresh cornice growth at upper elevations. Heavy loading from snow and rain, and the resulting avalanche cycle, has helped flush-out the mid- and early-January surface hoar/facet layers now down 80-120 cm deep. However, these layers are very much still intact and reactive in 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, especially in the Northern part of the region where the snow line stayed below treeline during the recent storm.

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

Possible - Likely

Expected Size

2 - 5

Wind Slabs

New snow, warm temperatures and wind on Tuesday 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.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 26th, 2016 2:00PM