Archived

Avalanche Forecast

Dec 23rd, 2016–Dec 24th, 2016

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

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

Regions: Lizard-Flathead.

Wind slabs sit above a weak mid-pack, creating the potential for small avalanches to step down to deeper layers.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

SATURDAY: Scattered flurries with 5-10 cm accumulations, light east winds, alpine temperature -10C.SUNDAY: Mix of sun and cloud, calm, alpine temperature -14C.MONDAY: Isolated flurries, moderate southwest winds, alpine temperatures -11C.

Avalanche Summary

Wind and storm slabs continue to be reactive to heavy explosive triggers, releasing size 2-2.5 avalanches on facets 60-100 cm deep. There is a bit of uncertainty regarding how last week's snow will bond to old surfaces that formed during the cold snap. Given this, there is still potential for skier and rider triggering in sheltered areas where buried surface hoar may exist, or in wind exposed terrain where wind slabs maybe sitting on facets.

Snowpack Summary

10-20 cm of new low density snow sits above 30-40 cm of settling storm snow from earlier this week. The storm snow sits above a variable surface that developed during the cold, dry, and windy conditions earlier this month and has been most reactive in wind-exposed terrain. The old interface consists of scoured surfaces and wind slabs in exposed terrain, weak faceted (sugary) snow, and surface hoar up to 20 mm in sheltered areas. In sheltered areas, you may find another layer of surface hoar and facets in the mid-pack that was buried around December 10. The thick crust from mid-November is near the bottom of the snowpack and reports suggest that the crust is currently well bonded to the surrounding snow.

Avalanche Problems

Wind Slabs

New snow adds to reactive wind slabs that sit over a variety of weak sliding layers. Use extra caution in steeper, wind-exposed terrain.

Watch for signs of instability such as whumpfing, or cracking. Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2