Archived

Avalanche Forecast

Jan 17th, 2013–Jan 18th, 2013

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: South Coast.

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.

Avalanche Problems

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

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

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