Avalanche Forecast

Issued: Mar 7th, 2019 4:27PM

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

Avalanche Canada kdevine, Avalanche Canada

Fresh storm slabs may be reactive to human triggering. Watch for signs of instability such as whumphing, cracking and recent avalanches.

Summary

Confidence

Moderate -

Weather Forecast

THURSDAY NIGHT - Mainly cloudy with isolated flurries, up to 5 cm / west winds 20-40 km/h / alpine low temperature near -11FRIDAY - Mainly cloudy with isolated flurries, 5 cm / west winds 10-20 km/h / alpine high temperature near -9SATURDAY - A mix of sun and cloud / northwest winds 10-15 km/h / alpine high temperature near -10SUNDAY - Sunny with cloudy periods / west winds 10-20 km/h / alpine high temperature near -8

Avalanche Summary

On Thursday, there were preliminary reports of size 1-1.5 loose avalanches, and size 1 human triggered storm slab avalanches.On Tuesday there was one size 1 human triggered persistent slab avalanche reported on a north aspect at 1100 m. It failed on the late January persistent weak layer, 40 cm deep and was triggered remotely (from a distance).Generally speaking, reports from the past week are mainly of wind slabs reacting to ski cuts, with a trend toward smaller (size 1) releases. Small (size 1-1.5) loose dry avalanches have also been observed releasing naturally from steeper, sun exposed slopes in recent days.Reports of human triggered persistent slab avalanches on the January weak layers have been on the decline, suggesting these layers have evolved into a lower likelihood/high consequence avalanche problem.

Snowpack Summary

10-25 cm of new snow sits on wind slabs, surface hoar (feathery crystals), and facets (sugary snow) and a crust on sun exposed slopes. The buried wind slabs are also sitting on facets and they may continue to be reactive. There are a two prominent weak layers in the upper snowpack that were buried in mid and late January. These can be found approximately 40-80 cm deep. Both layers consist of surface hoar and may be associated with a crust on steep, south facing slopes. These weak layers have been most reactive at lower elevations, and especially below treeline.The lower snowpack is generally considered to be strong, except for shallow, rocky areas where the cold temperatures continue to facet (weaken) the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
Fresh storm slabs may be reactive, especially in wind loaded areas.
Exercise increased caution around wind loaded pockets near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Persistent Slabs

An icon showing Persistent Slabs
Two persistent weak layers are buried approximately 40 cm and 80 cm. These layers have evolved into a lower likelihood/high consequence avalanche problem.
Maintain diligent group management around open and/or sparsely treed slopes at treeline and below.Exercise increased caution around low elevation cut-blocks where this layer has been well preserved.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Mar 8th, 2019 2:00PM