Avalanche Forecast

Issued: Feb 18th, 2019 4:02PM

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

william lawson, Parks Canada

Little Yoho.

Watch for windslabs in alpine lee areas and loose dry avalanches in steep terrain. Ski quality is currently excellent.

Summary

Weather Forecast

A slight increase in cloud and wind (up to moderate west) is expected for Tuesday and Wednesday. Some light flurries forecasted on Tuesday with 1-2cm of accumulation. Temperatures will stay civilized for the next few days with day time highs to -5. Overall, minimal weather inputs that will impact the danger rating.

Snowpack Summary

30 to 50 cm of snow has fallen since Feb 2. This has been affected by variable winds, isolated periods of solar radiation and most notably, sustained cold temperatures promoting faceting. 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

Problems

Wind Slabs

New snow and some light North wind have created new soft 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.

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

Valid until: Feb 19th, 2019 4:00PM