Archived

Avalanche Forecast

Feb 16th, 2018–Feb 17th, 2018

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

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

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.

Avoid avalanche terrain on Saturday. Intense snowfall and a reactive crust will make conditions very dangerous.

Confidence

High - on Saturday

Weather Forecast

SATURDAY: Heavy snow starting Friday night with 30-40 cm possible by the end of the day, strong south wind, freezing level around 700 m with alpine high temperatures around -2 C. SUNDAY: Some isolated flurries with clearing throughout the day, moderate northeast wind, freezing level dropping with alpine high temperatures around -6 C.MONDAY: Sunny with cloudy periods, light northeast wind, alpine high temperatures around -10 C.

Avalanche Summary

Storm snow on the crust has been reactive since Wednesday, producing both natural and skier-triggered avalanches in the size 1-2 range at treeline elevations. See here for an example.Expect storm slabs to become much thicker and touchier on Saturday given the poor bond between the new snow and the crust.

Snowpack Summary

Storm snow is accumulating above a hard rain crust that extends into alpine terrain. Reports indicate the snow is poorly bonded to the crust. By Saturday afternoon, storm slabs will likely be over 50 cm thick and become very touchy. There are no significant layers of concern below the crust.

Avalanche Problems

Storm Slabs

Thick storm slabs are forming above a widespread crust. Natural and human-triggered avalanches are very likely during the storm.

Avoid avalanche terrain during periods of heavy loading from new snow and wind.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely - Certain

Expected Size: 1 - 2.5

Cornices

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

Give cornices a wide berth when traveling on or below ridges.Firm cornices may 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