Avalanche Forecast

Issued: Jan 23rd, 2019 4:36PM

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

Avalanche Canada swerner, Avalanche Canada

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The recent snow continues to be touchy to human triggers, especially where a more cohesive slab exists above the weak interface. Areas that may catch you by surprise are open slopes, cutblocks and gullies at treeline and below.

Summary

Confidence

High -

Weather Forecast

Thursday: Mostly cloudy with moderate westerly ridgetop winds. Alpine temperatures near -3 and freezing levels rising to 800 m.Friday: Cloudy with isolated flurries and gusty northwest ridgetop winds. Alpine temperatures high of -1 and freezing levels 1000 m. Saturday: Mix of sun and cloud with light to moderate westerly ridgetop winds. Alpine temperatures high of +1 and freezing levels rising to 2500 m.

Avalanche Summary

A few skier triggered wind slab and persistent slab avalanches up to size 1.5 were reported on Tuesday. Those avalanches were commonly found from 2000 m and above. At lower elevations (treeline and below) you will likely see widespread dry loose sluffing from steeper terrain features as the upper snow above the surface hoar/ crust interface is mostly unconsolidated. In areas where there is wind effect or more cohesion in the upper snowpack, you can expect it to be a more reactive slab over the weak interface.Check out this MIN report for a great overview of conditions including photos.

Snowpack Summary

20-35 cm of snow sits above a layer of large feathery surface hoar crystals and sun crust. In areas that have had wind effect the recent snow has been settling into a thin but reactive slab above this weak layer, with enhanced reactivity noted at elevations between 1500-1800 metres where the surface hoar is particularly well developed on all aspects. In sheltered areas the snow is faceting, low density and lacks cohesion above this layer which is only reactive as dry loose sluffing. Forecast warmer temperatures will likely change this and promote increased slab properties this weekend.Strong winds associated with the new snow formed reactive wind slabs on leeward slopes and scoured southerly aspects down to the crust at upper elevations. The middle and lower portions of the snowpack are generally well-settled and strong.

Problems

Persistent Slabs

An icon showing Persistent Slabs
20-35 cm of snow sits above a weak interface of surface hoar and sun crust. Where the snow has formed a cohesive slab it is reactive to human triggering, especially between 1500m-1800m. Sluffing can be expected where there is not a slab.
Watch for whumpfing, hollow sounds, and shooting cracks.use extra caution around steep open terrain features, such as cutblocks, gullies and cutbanks.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 24th, 2019 2:00PM