Avalanche Forecast

Issued: Mar 12th, 2015 4:49PM

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

ian jackson, Parks Canada

Banff Yoho Kootenay.

In eastern areas of the forecast region (Banff area), the danger rating will be higher as repeated days of warm weather with little overnight recovery is taking its toll on the snowpack. Temperatures have been cooler along the continental divide.

Summary

Weather Forecast

Friday should be partly cloudy with a weak freeze in the AM but some clouds to keep the solar radiation at bay. Forecasts are calling for a short but intense storm starting Saturday around noon which should deposit 20 - 30 cm's of new snow above 2000m with rain below. Alpine winds will be moderate to strong from the W/ SW throughout the period.

Snowpack Summary

There is a wide range of conditions from east to west at this time. Eastern areas (Banff) are subject to the warm temperatures which are effecting the snowpack on S and W aspects. Further west the temperatures have remained cool enough that treeline and alpine snowpacks have remained solid and new snow has made fresh windslabs in the alpine.

Avalanche Summary

No new avalanches observed or reported today.

Confidence

Timing of incoming weather systems is uncertain on Saturday

Problems

Wind Slabs

5 - 10 cm's of new snow has been blown by strong west winds into small windslabs in the alpine. In some areas this covers isolated areas of older windslab that has been reactive to human triggering over the past week.

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

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

The warm temperatures will create wet sluffs and rockfall on south facing slopes and gullies at and below treeline. Ice climbers should avoid this terrain, and instead search for north facing climbs where the cold temperatures will keep things solid.

Plan to be off big slopes before the temperatures rises and the snowpack deteriorates.Travel conditions are difficult at lower elevations and in the trees.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

The lower half of the snowpack is weak due to the presence of basal facets and depth hoar. This layer has been dormant lately but may waken up with the warm temperatures (especially east of the divide where temperatures have been warmer)

Avoid thin, rocky or sparsely-treed slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 13th, 2015 4:00PM