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Archived

Avalanche Forecast

Dec 7th, 2016–Dec 8th, 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
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: Lizard-Flathead.

Avoiding steep slopes where wind has deposited fresh snow is the key to managing avalanche hazard under the current conditions.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Thursday: Dry and bright. Very cold - treeline temperatures around -25 C. Winds light from the east. Friday: A few flurries, with only minimal accumulation. Winds increasing to 25-35 km/hr at ridgetop from the south. Temperatures remaining very cold. Saturday: 2-4 cm new snow expected. Winds 25-35 km/hr from the southwest. Warming to a balmy -22 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. These failed on NE-N aspects above 1750 m on, 50-100 cm deep, 50-100 m wide and running up to 500 m in length. These avalanches were reported to be failing on a previous graupel (small hail) interface and not digging deeper to the November crust layer. On Monday, numerous loose dry avalanches up to size 1 were reported after the storm as well as a natural size 2.5 storm slab from a northeast aspect above 1800 m. The crown was 20-100 cm thick, 150-200 m wide and running 500 m in length.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2