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Avalanche Forecast

Feb 20th, 2017–Feb 21st, 2017
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
1: Low
The avalanche danger rating at treeline will be low
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
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

Watch for lingering wind slabs in high north facing terrain and wet sluffing on steep sun exposed slopes.

Confidence

Moderate -

Weather Forecast

A mix of sun and cloud is expected on Tuesday with possibility of isolated flurries. Alpine wind is expected to be light and afternoon freezing levels are forecast to reach around 1000 m. Similar conditions are expected for Wednesday and Thursday with a mix of sun and cloud, light alpine wind, and treeline temperatures around -10C.

Avalanche Summary

On Sunday, avalanche activity was limited to ski cutting producing a few size 1 soft slabs which were 10-15 cm thick and isolated to the most recent storm snow. On Saturday, explosives released two large cornices which did not trigger slabs on the slopes below. On Tuesday, lingering wind slabs are the main concern. Look for these in immediately leeward features on northerly aspects in exposed terrain.  Sluffing from steep sun exposed slopes is also possible during the heat of the afternoon.

Snowpack Summary

15-20 cm of new snow accumulated Sunday overnight. At higher elevations, the widespread mid-February melt-freeze crust is now typically down 30-60 cm. This crust extends as high as 2200 m and is up to 15 cm thick at treeline. The recent storm snow is reported to be bonding well to the crust. In the alpine, wind slabs and cornices were recently being reported on northerly aspects. Below around 1900 m, the crust is at or near the surface of the snowpack and is reported to be supportive to the weight of skier.

Avalanche Problems

Wind Slabs

Reactive wind slabs may still be lingering in high north facing terrain. Large lingering cornices may also still be weak and could fail under the weight of a person.
Use ridges or ribs to avoid pockets of wind loaded snow.Avoid areas where the surface snow feels stiff or slabby.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Loose Wet

It may be possible to trigger wet sluffs on steep sun exposed slopes during the heat of the afternoon.
Be cautious of sluffing in steep terrain.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 2