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Avalanche Forecast

Feb 15th, 2018–Feb 16th, 2018
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
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: Sea To Sky.

Wind slabs at higher elevations continue to be the main concern. Approach steep features cautiously.

Confidence

High - on Friday

Weather Forecast

FRIDAY: Trace to 5 cm of new snow by the morning then clearing throughout the day, moderate west wind, freezing level climbing to 1000 m with alpine high temperatures around -5 C.SATURDAY: Moderate snowfall with 15-25 cm throughout the day, strong southwest wind, freezing level up to 800 m with alpine high temperatures around -5 C.SUNDAY: Clearing and cooling with strong northeast wind and alpine high temperatures around -14 C.

Avalanche Summary

No new avalanches have been reported on Thursday (as of 4 pm). On Wednesday, a few small isolated size 1 storm slabs were reactive to skiers and few large (size 2-2.5) natural slab avalanches were reported in steep rocky terrain and lee features. Cornices were reactive to explosive triggers, some producing small slabs on the slopes below.Several large cornices have collapsed over the past week. One resulted in a fatal accident in the Callaghan area on Saturday. A snowmobiler was parked 7-10 m back from the edge of a corniced ridge when a large chuck broke off and took the rider down the slope. See here for a full report. A similar incident occurred nearby the same day, but the person only suffered minor injuries. A collapsing cornice also triggered a large slab (size 3) on a north-facing slope west of Pemberton on the weekend. Fragile cornices continue to be a concern in the region.

Snowpack Summary

10-20 cm of light snow sits above a variety of old surfaces, including scoured crusty surfaces on south-facing alpine slopes, a melt-freeze crust up to about 1900 m, and old wind slabs on a range of aspects at high elevations. The mid-January crust is now buried beneath 150-200 cm of settled snow, but a heavy trigger such as a cornice fall could potentially wake up this layer. The lower snowpack is generally strong and well-settled.

Avalanche Problems

Wind Slabs

Watch for fresh wind slabs forming at higher elevations. Also be suspicious of steep features that may have been previously wind loaded.
Approach steep lee and cross-loaded slopes with caution.Use ridges or ribs to avoid pockets of wind loaded snow.Be alert to conditions that change with elevation.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Cornices

Large, looming cornices have formed along ridgelines. They need to be given an extra wide berth from above and below. A large cornice collapse in the wrong location may have the ability to trigger a large avalanche on the slope below.
Stiff cornices can easily pull back into flat terrain at ridgetop if they fail.Falling cornices may trigger large avalanches on the slopes below.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2.5