Avalanche Forecast

Issued: Mar 20th, 2018 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

The first day of spring was a blustery one near Lake Louise! The winds have destroyed the good quality surface snow and changed the conditions dramatically in the past 24-hours. This is not the case everywhere and some areas have received new snow.

Summary

Weather Forecast

The unsettled weather continues again on Wednesday with clouds and a few flurries ending by noon - the afternoon should see some clearing and freezing levels reaching 2100 m. Friday might be the snowy day this week and temperatures are forecast to fall below -15 for the start of the weekend.

Snowpack Summary

Convective flurries have deposited new snow in some areas of the park and not in others, so the surface conditions are quite variable. 24-hr of wind near Lake Louise has created widespread wind effect in all open terrain at treeline and in the alpine. On south and west aspects these slabs may bond poorly to a suncrust down approximately 30-50 cm.

Avalanche Summary

A size 1 windslab was triggered by skiers on a classic leeward slope under a cornice today - 25 cm deep by 50 m wide. Several large avalanches have been triggered by skiers over the past few days - these seem to be in isolated locations but the common theme has been West aspect on suncrust.

Confidence

Problems

Wind Slabs

24 hours of sustained winds from the SW has created windslabs up to 30 cm thick in leeward areas, mostly in the alpine. The are unlikely to release naturally but can be triggered by skiers and climbers.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

On steep solar terrain the recent storm snow (20-30cm) is sitting on a suncrust that was buried on March 15. These types of problems can be tricky due to their isolated nature, but be cautious on any steep south or west facing terrain in the alpine.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Mar 21st, 2018 4:00PM