Archived

Avalanche Forecast

Feb 14th, 2018–Feb 15th, 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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Sea To Sky.

Wind slabs exist on a wide range of aspects and may be hidden by the most recent snow.

Confidence

High - on Thursday

Weather Forecast

THURSDAY: Increasing cloud with light flurries in the evening, light to moderate west wind, alpine high temperatures around -10 C.FRIDAY: Trace to 5 cm of new snow by the morning then clearing throughout the day, light northwest wind, freezing level climbing to 1000 m with alpine high temperatures around -6 C.SATURDAY: Moderate snowfall with 10-20 cm throughout the day, strong southwest wind, freezing level up to 900 m with alpine high temperatures around -6 C.

Avalanche Summary

The new snow produced a few small isolated size 1 avalanches on Wednesday. No new avalanches were reported on Tuesday.Some larger wind slabs were reactive to skier triggers on the weekend, including a size 2 avalanche on a north-facing slope near Whistler on Saturday (see MIN report here).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 new snow sits above a variety of old surfaces, including scoured crusty surfaces on south-facing alpine slopes, old wind slabs on a range of aspects at high elevations, and a melt-freeze crust up to about 1900 m. On average, 180 cm of settled snow now sits on the mid-January crust which generally shows signs of bonding to the overlying snow; however, it has the potential to wake up with a large trigger such as a cornice fall. Below this, the snowpack is thought to be generally strong and well-settled.

Avalanche Problems

Wind Slabs

Light amounts of new snow and strong wind has formed new wind slabs and buried older wind slabs on a range of aspects.

Use ridges or ribs to avoid pockets of wind loaded snow.Approach steep lee and cross-loaded slopes with caution.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

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.

Falling cornices may trigger large avalanches on the slopes below.Stiff cornices can easily pull back into flat terrain at ridgetop if they fail.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2.5