Avalanche Forecast

Issued: Jan 18th, 2013 9:32AM

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

jlammers, Avalanche Canada

South Coast.

Summary

Confidence

Good

Weather Forecast

Mainly clear skies are expected for the forecast period. Winds should remain generally light from the southwest with daytime temperatures hovering around 4.0.

Avalanche Summary

Recent observations mostly involve snowballing and several wet loose sluffs up to Size 1.5 on sun-exposed slopes. Daytime warming probably contributed to a size 2.5 slab avalanche that most likely failed on the crust/facet combo near the ground in Gates Lake area (NW of Pemberton) on Wednesday. The slide, which was 100m wide and 200m long, released on a west aspect at 1800m, and had a crown of 80-150cm.

Snowpack Summary

Above freezing temperatures at higher elevations have caused snow surfaces to moisten on sun-exposed slopes; however, a nightly crust recovery is likely with the cooler temperatures and clear skies. The surface snow on northerly aspects is dry and wind affected with continued surface hoar growth at lower elevations. Below this, 40-80 cm of settling storm snow sits on a persistent weakness of buried surface hoar, facetted snow, and /or a crust. Recent snowpack tests show that this interface is gaining strength but is likely still susceptible to human triggering with potential to propagate widely. No significant weaknesses have been reported recently below this in the mid snowpack layers. Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by warming or heavy triggers in steep, shallow, rocky terrain where more facetting has taken place.

Problems

Loose Wet

Loose wet activity is expected with ongoing warm temperatures. Watch for triggering in steep, sun-exposed terrain.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Strong variable winds have produced wind slabs in exposed lee and cross-loaded terrain. Some of these windslabs now exist on solar aspects may may release due to daytime warming.

Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A buried weakness, down 40-80 cm, may become more reactive as a result of daytime warming. Watch for triggering

Conditions have improved, but be mindful that persistent instabilities are still present.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Jan 19th, 2013 2:00PM