Archived

Avalanche Forecast

Feb 17th, 2018–Feb 18th, 2018

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

3: Considerable

The avalanche danger rating below treeline will be considerable

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

3: Considerable

The avalanche danger rating below treeline will be considerable

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: South Coast.

Human-triggered avalanches are likely. Storm snow will take longer than usual to gain strength.

Confidence

Moderate -

Weather Forecast

SUNDAY: A few light flurries in the morning and then clearing and cooling as Arctic air pushes into the region, moderate northeast wind, alpine high temperatures around -10 C.MONDAY: Sunny, light wind, alpine high temperatures around -10 C.TUESDAY: Mostly sunny, light wind, alpine high temperatures around -8 C.

Avalanche Summary

Storm snow was very reactive on Saturday, with numerous reports of size 1-2 slab avalanches being triggered by skiers, including remotely (from a distance). Activity occurred on all aspects at both treeline and below treeline elevations. Conditions were likely similar in alpine terrain.

Snowpack Summary

Recent snowfall has buried a hard rain crust that extends into alpine terrain. The crust is now roughly 40 cm below the surface, and reports suggest the snow will take several days to bond to the crust. The result is a very touchy storm slab above the crust. There are no significant layers of concern below the crust.

Avalanche Problems

Storm Slabs

Storm slabs will remain very reactive to human triggers on Sunday. Surprisingly wide propagations are possible because of the buried crust.

Be very cautious near open slopes and convex rollsUse caution above cliffs and terrain traps where small avalanches may have severe consequences.Use careful route-finding and stick to moderate slope angles with low consequences

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 2

Cornices

Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect. Give them a wide berth from above and below.

Firm cornices may pull back into flat terrain at ridgetop if they fail.Give cornices a wide berth when traveling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2