Archived

Avalanche Forecast

Feb 19th, 2019–Feb 20th, 2019

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Banff Yoho Kootenay.

Dry good ski conditions continue, watch for small amounts of loading from light to moderate winds which will produce windslabs in the alpine and treeline.

Weather Forecast

For Wednesday we expect Light to Moderate Northerly winds switching to North East in the afternoon, temperatures from -15 to -5 and trace amounts of new snow.

Snowpack Summary

30 to 50 cm of snow has fallen since Feb 2. Recent new snow has been affected by Light to Moderate westerly winds. Cold conditions continue promoting faceting of the snowpack. Down 30 to 75cm, Jan 17 surface hoar produces sudden planar shears in isolated locations treeline an below. A weak basal snowpack exists in shallow areas.

Avalanche Summary

Several reports of both skier triggered wind slabs and loose dry avalanches have been noted this past week. Generally these avalanches have been small (size1-2) but have been running far, entraining the loose faceted surface snow.

Confidence

Due to the number and quality of field observations

Avalanche Problems

Wind Slabs

New snow and Light to Moderate westerly winds have created wind slabs. These slabs have yet to produce anything larger than a size 2.

Variable winds may create pockets of wind slab in some unexpected locations.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Loose Dry

A sustained period of cold weather has driven the faceting process in the upper snowpack creating weak, dry surface snow. In steep terrain, these are sensitive to small natural and human triggers and can quickly gain enough mass to affect travelers.

Good group management is essential to manage current conditions safely.Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 1.5