Avalanche Forecast

Issued: Feb 24th, 2014 7:28AM

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

Peter, Avalanche Canada

Sea To Sky.

Don't let blue skies and fresh snow lure you into big terrain! A buried persistent weak layer is still lurking and could wake up with forecast sunshine and rapidly rising temperatures.

Summary

Confidence

Fair

Weather Forecast

Synopsis: A building upper ridge of high pressure will result in drier conditions and more sunshine for the next several days. Temperatures will also increase dramatically by Tuesday. Tuesday: A mix of sun and cloud. The freezing level jumps as high as 2500 m with treeline temps around +3. Winds are light and variable. Wednesday: A mix of sun and cloud. The freezing level jumps remains near 2500 m with treeline temps ranging from +5. Winds are light and variable.Thursday: Cloudy with sunny breaks and a chance of light precipitation. The freezing level is near 2000 m.

Avalanche Summary

There was a report of a size 2 remotely triggered slab avalanche in the Whistler backcountry on Saturday. The slab depth was reported to be approximately 1.5 m deep, likely failing on a facet/crust combo. There was also a report of a size 2 accidentally skier triggered avalanche in the Blackcomb backcountry on Friday. Check out Wayne Flann's Avalanche Blog for photos of both of these incidents. Expect loose dry avalanches in steep terrain and the potential for triggering thin wind slabs in exposed lee terrain, especially on steep and unsupported slopes.

Snowpack Summary

Up to 50 cm of cold low density snow has fallen in the past few days, with light winds forming fresh thin wind slabs near ridge crests. 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

Warming temperatures and solar radiation will likely increase the probability of triggered the mid February persistent weak layer, that is now down 80-150 cm.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Wind Slabs

Thin new wind slabs have formed on exposed lee and cross-loaded slopes and could be triggered by the weight of a rider. Also, give cornices a wide berth as temperatures start to climb.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Wet

A loose wet avalanche could drag you somewhere you don't want to end up, but could also be enough mass to trigger a large slab avalanche.

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

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Feb 25th, 2014 2:00PM