Avalanche Forecast

Issued: Jan 17th, 2013 9:37AM

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.

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Mainly clear skies are expected for the forecast period as a static ridge of high pressure continues to dominate the region. For the next 3 days, winds will be mostly light and variable with alpine temperatures hovering between 0.0 and 3.0.

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). 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 on sun-exposed slopes, breaking down the 1-2cm surface crust, and weakening wind slabs. The surface snow on northerly aspects has been remaining dry with continued surface hoar growth. 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 heavy triggers in steep, shallow, rocky terrain where more facetting has taken place.

Problems

Loose Wet

An icon showing Loose Wet
Loose wet activity is expected as temperatures rise. A loose wet slide could step down and trigger weaknesses deeper in the snowpack.
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

Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
Strong northwesterly 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.
Avoid travelling in areas that have been reverse loaded by winds.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
A buried weakness, down 40-80 cm, may become reactive as a result of intense daytime warming.
Conditions have improved, but be mindful that deep instabilities are still present.>Be aware of the potential for large avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Jan 18th, 2013 2:00PM