Archived

Avalanche Forecast

Dec 8th, 2016–Dec 9th, 2016

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

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: Lizard-Flathead.

Lookout for stiff wind slabs in the alpine. Likely trigger spots are steep and rocky alpine terrain with a shallow snowpack.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Friday: Cloudy with isolated flurries / Light easterly winds / Weak inversion with a alpine high of -15 C.Saturday: Cloudy with scattered flurries and 3-5 cm new snow / Light to moderate southerly winds / Alpine high -11 C.Sunday: 5-10 cm new snow overnight / Mostly cloudy / Moderate southwesterly winds / Alpine high of -12 C.

Avalanche Summary

Avalanche activity continues to taper since the last storm. On Wednesday, explosive avalanche control triggered only small size 1 slabs. On Tuesday, explosive control triggered numerous slab avalanches up to size 2.5 on northerly aspects above 1750m. These avalanches were reported to be failing on a previous graupel (small hail) interface and not digging deeper to the November crust layer.

Snowpack Summary

Recent storm slabs and wind slabs have formed on open leeward slopes and behind terrain features in exposed areas. The mid pack is reported to be well settled. There is sufficient snow on the ground for avalanches at treeline and alpine elevations, and possibly in some below treeline locations. Reports suggest typical treeline snow depths are around 110-150 cm, but a report from the east side of region indicated a much lower snow depth of around 90 cm. Limited reports suggest the crust from the middle of November is down 50-80 cm and the crust from early November is down 80-110 cm.

Avalanche Problems

Wind Slabs

New snow accompanied by strong winds have formed fresh and reactive storm slabs at upper elevations. Watch leeward slopes or terrain features that show signs of wind effect, like cracking and whumpfing below your feet.

Use ridges or ribs to avoid pockets of wind loaded snow.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2