Archived

Avalanche Forecast

Dec 17th, 2017–Dec 18th, 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

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

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: Sea To Sky.

Wind-blown snow is driving the avalanche danger on Monday. Watch for how the new snow is bonding to the old surface.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

Monday will see a brief lull in the active weather pattern before significant precipitation arrives on Tuesday.MONDAY: Cloudy with isolated flurries. Accumulation of 5 cm possible. Ridge wind light from the west. Temperature near -2. Freezing level 800 m.TUESDAY: Snow. Accumulation 15-25 cm. Ridge wind moderate from the southeast. Temperature near -4. Freezing level 500 m. WEDNESDAY: Sunny with cloudy periods. Ridge wind moderate northerly. Freezing level 600 m.

Avalanche Summary

On Sunday, natural and cornice triggered storm slabs to Size 1 were reported on northerly aspects in the alpine. Avalanche activity is expected to increase with the wind-driven snow on Monday, especially on north through east aspects at higher elevations.

Snowpack Summary

10-20 cm of new snow covers the melt-freeze crust that formed on all aspects and elevations in early December. On high north aspects this crust is thin with dry, sugary snow crystals (facets) below. Moderate winds from the south (west) have redistributed snow, creating isolated soft slabs on downwind slopes and behind ridges (north through east aspects). Beneath the surface, the upper snowpack is well settled and overlies a thin layer of facets on the late-November rain crust, which is now down approximately 60 cm at tree line elevations. The lower snowpack is well settled and consists of several crusts that formed in the early season.

Avalanche Problems

Wind Slabs

The new storm snow may be easily triggered, especially in areas with additional loading from wind.

Watch for signs of instability such as whumpfing, shooting cracks or recent natural avalanches.Be cautious as you transition into wind affected terrain.Be careful with wind loaded pockets in down wind areas, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3