Archived

Avalanche Forecast

Apr 15th, 2017–Apr 16th, 2017

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

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

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

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: Cariboos.

Falling cornices continue to trigger large avalanches. Solar radiation and rapidly rising freezing levels make this a very real possibility on Sunday.

Confidence

High -

Weather Forecast

SUNDAY: Sunny. Light Southerly ridgetop winds. Freezing level RAPIDLY RISING to 1900 m.MONDAY: Mix of sun and cloud with isolated flurries. Light southerly ridgetop winds. Freezing level around 1600m.TUESDAY: Cloudy with flurries. Light southeasterly ridgetop winds. Freezing level rising to around 1900m.

Avalanche Summary

A size 2.5 deep persistent slab avalanche which was triggered by a cornice fall and failed on facets at the bottom of the snowpack was reported southwest of Valemount on Friday. The key weather factor to keep your eye on this weekend will be the sunshine accompanied by rising freezing levels. These are common trigger for cornices which is currently our primary concern due to their ability to trigger large avalanches.

Snowpack Summary

Cornices are large, looming, and the primary concern due to their potential to trigger large avalanches failing on sugary facets near the bottom of the snowpack. Convective snow showers and moderate southwesterly winds have formed small wind slabs below alpine ridgetops. Solar radiation is a common trigger for loose wet avalanching in steep terrain, especially when new snow gets heated by the sun for the first time.

Avalanche Problems

Cornices

Avoid all slopes that are threatened by cornices on Sunday.

Cornice failures could trigger large avalanches on sugary facets near the bottom of the snowpack.Cornices often break further back than expected; give them a wide berth when traveling on ridgetops.

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

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 2 - 3

Wind Slabs

Convective flurries and moderate southwesterly winds have created wind slabs in lee features at treeline and above.

Be cautious with wind loaded pockets near ridge crests and roll-overs.Use ridges or ribs to avoid pockets of wind loaded snow.Keep an eye out for reverse loading created by shifting winds.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Loose Wet

Small loose wet avalanches have the potential to trigger large avalanches on sugary facets near the bottom of the snowpack.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Solar radiation is a common trigger, especially where new snow is sitting on a crust.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2