Avalanche Forecast

Issued: Feb 25th, 2014 8:32AM

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

triley, Avalanche Canada

Sea To Sky.

Forecast sun and high freezing levels may increase the danger from loose wet avalanches and avalanches stepping down to the deeply buried weak layer.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Wednesday

Weather Forecast

Overnight and Wednesday: Warm air is expected to be trapped in the alpine overnight. The freezing level is expected to rise to near 2500 metres during the day. Some cloud and moderate Southwest wind are expected to develop during the afternoon.Thursday: Continued warm air at higher elevations. Wind becoming moderate Northerly and the freezing level dropping down to valley bottom Thursday night.Friday: Mostly clear with moderate Northwest winds and freezing levels rising to about 1000 metres.

Avalanche Summary

Moist or wet loose snow avalanches were reported up to size 1.0 on solar aspects. A couple of natural slab avalanches size 2.0 were reported from the Whistler backcountry on South-Southwest aspects that may have been triggered by the rapid settlement of the recent snow above the early February weak layer.

Snowpack Summary

Strong solar radiation quickly settled the 30-50 cm of recent cold low density new snow. Solar aspects becoming moist and then developing a thin melt-freeze crust during developing cloud in the afternoon. The prominent mid-February weakness, which is primarily a facet/crust combo (with surface hoar in some areas), is now 80-160 cm deep depending on wind exposure. Recent snowpack tests give variable results on this layer, but some observers are still reporting sudden "pops or drops" shears and continue to experience whumpfs. Previous strong winds created wind slabs in exposed lee and cross-loaded terrain, which are now hidden by the dry new snow. The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region; however, skier triggering has become unlikely.

Problems

Persistent Slabs

The deeply buried early February weak layer continues to be sensitive to additional loads. Continued warming and settling of the storm snow may result in more activity on this layer.

Use conservative route selection, stick to moderate angled terrain with low consequence.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack. >Stick to simple terrain and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Wind Slabs

Some areas received strong Easterly outflow winds that may have developed new soft wind slabs on slopes that are often stripped by the prevailing Southwest winds.

Use ridges or ribs to avoid pockets of wind loaded snow.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Wet

Forecast strong solar radiation and high freezing levels may result in loose moist or wet avalanches on Southerly aspects. Avalanches in motion may step down to the early February weak layer resulting in large slab avalanches.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Feb 26th, 2014 2:00PM