Avalanche Forecast

Issued: Dec 18th, 2016 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

The incoming weather system will lead to an increase in danger levels. The more significant increase is likely to occur Tuesday, but keep an eye on localized conditions if more snow falls than is anticipated on Monday.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

A low pressure system is approaching, but it is unclear as to how much snow we will get. Models vary from 10 to 15cm by Tuesday. What is clear is that the winds will be strong to extreme from the West for the next few days. Monday will remain cool with a high of only -15 °C, but Tuesday should be a bit warmer.

Avalanche Summary

Numerous loose dry avalanches up to size 2.0 in steep Alpine and Treeline terrain were observed today. Field teams did ski cut a few wind slabs up to 30cm deep that were in the size 1.0 to 1.5 range in wind affected terrain below ridge crests in immediate lees.

Snowpack Summary

Variable wind slab conditions exist in the Alpine and open areas at Treeline. Strong winds today are contributing further to this issue. The November 12th crust layer is buried 50 to 70cm and continues to give widely variable test results, indicating the need to carefully evaluate each terrain feature. Otherwise the snowpack is weak and facetted after almost 2 weeks of continuously cold temperatures.

Problems

Loose Dry

Very strong winds have increased the frequency and magnitude of loose dry avalanches. Numerous slides were observed today up to size 2.0. This trend will continue Monday with incoming snow and strong winds.

Carry avalanche safety equipment on ice climbs in avalanche terrain.Be cautious of sluffing in steep terrain.Avoid travelling on ledges and cliffs where sluffing may have severe consequences.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Wind Slabs

Wind slab distribution is highly variable across the terrain. These slabs seem to be more sensitive to human triggering today (several failures noted by field teams), and if triggered they could step down to the November crust layer.

Use caution on open slopes and convex rolls Watch for areas of hard wind slab in steep alpine features.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 19th, 2016 2:00PM