Avalanche Forecast

Issued: Feb 26th, 2014 8:03AM

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

Avalanche Canada triley, Avalanche Canada

Above freezing alpine temperatures are expected to continue. Check out the new Forecaster Blog for an update on the “Touchy Weak Layer.”

Summary

Confidence

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

Weather Forecast

Overnight and Thursday: Warm air is expected to be trapped in the alpine overnight (temperature inversion), and continue to bring above freezing temperatures to the alpine on Thursday. Light Southwest winds are forecast overnight becoming Northerly when the arctic front slides down from the North. There is a chance of flurries Thursday evening depending on the timing of the cooler air.Friday: Freezing levels should drop down to valley bottoms overnight and then rise up to about 1000 metres with strong solar radiation and gusty Northeast outflow winds.Saturday: Clear and cold overnight. Gusty strong Northerly outflow winds becoming light Westerly as cloud moves into the region in the afternoon.

Avalanche Summary

Natural avalanches up to size 3.0 were reported from the Whistler backcountry on Tuesday, these avalanches were sliding on the early February persistent weak layer of facets and crusts. Suspect that loose wet snow is releasing naturally due to above freezing temperatures in the alpine and strong solar radiation.

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

An icon showing Persistent Slabs
The deeply buried weak layer continues to be sensitive to additional loads. Cornice falls or loose wet avalanches in motion may trigger the deep weak layer of facets and crusts.
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

Expected Size

2 - 5

Loose Wet

An icon showing Loose Wet
Forecast solar radiation may release loose moist or wet snow avalanches. Avalanches in motion may step down to the deeply buried weak layer of facets and crusts.
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 27th, 2014 2:00PM