Avalanche Forecast

Issued: Mar 27th, 2014 9:00AM

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

triley, Avalanche Canada

Sea To Sky.

The forecast new snow and wind should increase the avalanche danger. If the storm comes early the danger may be high by Friday afternoon.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Friday

Weather Forecast

Overnight and Friday: Freezing level dropping down to about 600 metres overnight. Snow starting in the early morning near the coast and moving inland as a warm front moves across the region. Expect 15-20 cm of snow near the coast, and 10-15 cm inland during the day. Southwest winds should build to strong values by the afternoon and freezing levels should rise to about 1500 metres.Saturday: A trailing cold front should bring another 15-20 cm of snow to near coastal areas and 5-10 cm further inland by morning. Winds should slow to moderate Southwest during the day as snow continues. Freezing level rising to about 1500 metres during the day.Sunday: Snow ending overnight or early morning. Light Southerly winds and freezing levels rising to about 1300 metres.

Avalanche Summary

No new reports of avalanches.

Snowpack Summary

The recent snow is expected to settle and bond to the mix of old surface crusts and wind slabs with daytime warming and overnight freezing levels dropping down to near valley bottoms. The forecast new snow and strong Southwest winds are expected to develop new storm slabs over the next few days that may release down to the old surface ofÂ melt-freeze crusts and/or where facets are sitting on old wind slabs. The added load of storm snow or storm slab avalanches in motion may trigger the March persistent weak layer. The early-March crust/facet layer is down about 100-150 cm and the early February layer is now down close to 200 cm.

Problems

Storm Slabs

Expect a new storm slab to start to develop during the day. The recent snow has not had a lot of time to settle and bond, and there may be areas where the old storm slab could be triggered by light additional loads.

Use ridges or ribs to avoid pockets of wind loaded snow.>Minimize exposure during periods of heavy loading from new snow, wind.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

Forecast snow and wind may develop fresh new cornices that could fall off naturally and trigger the deeply buried weak layers. Storm snow avalanches in motion may also trigger these weak layers resulting in very large avalanches.

Extra caution needed around cornices with current conditions.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Be aware of the potential for large, deep avalanches.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 28th, 2014 2:00PM