Avalanche Forecast

Issued: Mar 16th, 2018 9:01PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

The new snow remains reactive to human triggering especially in the East where the up slope storm dumped the most snow. Watch the weather inputs Saturday as more than 10 cm of new snow could easily increase the danger again.

Summary

Weather Forecast

Temperatures Friday should stay below freezing at treeline and alpine elevations while valley bottoms may be just above 0'C. Another 10 cm of snow from an upslope storm is expected on Saturday so again we expect more snow in the East than the West.

Snowpack Summary

20-30 cm of new snow from the past two days has formed a soft slab and is poorly bonded to the melt freeze crust and older snow layers below. Below this the majority of the snowpack is stable and recent tests have not found any weaknesses. Shallow areas are heavily facetted.

Avalanche Summary

The local ski hills reported numerous storm slabs running fast and far on all aspects and at all elevations on Thursday, as well as lots of sluffing in steep terrain. Several new storm slabs were noted in Yoho, Banff and Kootenay on Friday up to size 2 and are a good indication that the problem is still present.

Confidence

Intensity of incoming weather systems is uncertain on Saturday

Problems

Loose Dry

20-30 cm of snow in the last 24hrs has been sluffing naturally in steep terrain and is reactive to skiers. Wind, warm temps or sunny breaks will also increase the likelihood of this. Avoid steep confined terrain until the new snow settles and bonds.

The volume of sluffing could knock you over; choose your climb carefully and belay when exposed.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Storm Slabs

20-30 cm of new snow is forming a soft slab and has been reactive to skier triggering. Places where this slab sits over a melt freeze crust may be the most likely to fail, but all steep terrain will be suspect for the next day or two.

The storm slab may be more sensitive to human triggering on solar aspects where it sits on sun crustUse caution in lee areas in the alpine and treeline. Storm snow is forming reactive slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 17th, 2018 4:00PM