Avalanche Forecast

Issued: Feb 20th, 2018 4:44PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs and Cornices.

swerner, Avalanche Canada

South Coast.

The snow is heavily wind-affected. Triggering a wind slab is more likely on southerly slopes where a poor bond to the buried crust exists. Stick to sheltered trees to find the best and safest riding.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

A fairly benign weather pattern through the forecast period.Wednesday: Mostly cloudy with some sunny periods and a chance of flurries. An alpine high temperature of -8 with generally light westerly winds and some strong gusts.Thursday: Mostly sunny with an alpine high temperature of -5. Ridgetop winds light to moderate from the northeast.Friday: Cloudy with new snow 5-15 cm. Alpine temperatures near -3 and ridgetop winds moderate with strong gusts from the southwest.

Avalanche Summary

Dry loose avalanches up to size 1 were reactive to skier traffic on Monday.

Snowpack Summary

In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. In sheltered terrain, cold weather is preserving 30-50 cm of low density snow. A hard rain crust that extends into alpine terrain is buried about 40 cm beneath the recent storm snow. Reports suggest the snow has a poor bond to the crust with test results showing sudden planar characteristics. This means there's a potential for slab avalanches on any steep or convex terrain feature. Monitor the bond of the snow to this crust closely. There are no significant layers of concern below the crust.

Problems

Wind Slabs

Strong northerly winds have formed fresh slabs at higher elevations. Wind slabs may be more reactive to human triggers on solar aspects where they sit on a buried crust. Loose dry sluffing is likely from steeper terrain features.

Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect.

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.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Feb 21st, 2018 2:00PM