Avalanche Forecast

Issued: Feb 26th, 2019 3:34PM

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

Avalanche Canada dsaly, Avalanche Canada

Strong outflow winds have produced wind slabs on various aspects and cross-loaded terrain. The best riding will likely be found in sheltered areas with limited wind effect.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

TUESDAY NIGHT: Clear. Alpine temperatures near -4C. Ridgetop winds 15-25 km/h from the east-northeast.WEDNESDAY: Mostly sunny. Alpine temperatures near -3C, freezing level rising to 800 m. Ridgetop winds 25-35 km/h from the east.THURSDAY: Sunny with cloudy periods. Alpine temperature near -5C, freezing level around 700 m. Ridgetop winds 15-25 km/h from the northeast.FRIDAY: Mainly cloudy with isolated flurries, trace to 5 cm. Alpine high temperatures near -8C. Ridgetop winds 20-25 km/h from the east-southeast.

Avalanche Summary

A reactive slab has been reported in the mountains around Shames over the past few days. On Monday, a group of skiers remotely triggered a size 2.5 wind slab avalanche from 300 m away. The avalanche failed on a west aspect around 1600 m with a 50 cm crown. On Sunday, several small (size 1) avalanches were triggered by skiers descending in adjacent terrain on west to south alpine features. Similarly, a touchy and reactive snowpack was reported on the MIN around the Shames backcountry on Sunday documenting skier-triggered wind slab avalanches size 1-1.5 on south-southeast aspects (See one report here).On Saturday, while traversing a bench feature skiers north of Terrace remotely triggered 3 small (size 1) storm slab avalanches in steep terrain. A helicopter also remotely triggered a larger size 2 storm slab avalanche. The Saturday avalanches occurred in similar steep terrain on west to north aspects around 1300 m and failed 30-50 cm deep on the recently buried surface hoar layer.

Snowpack Summary

Strong outflow winds redistributed last weekend's snow, reshaping alpine and exposed treeline snow surfaces, and building variable wind slabs. Recent cold temperatures have encouraged surface hoar growth and surface faceting in sheltered terrain.In most areas, the 20-50 cm recent snow collectively overlies hard, previously wind affected surfaces or crust on solar aspects. In selective sheltered areas, low density snow overlies facets and/or spotty surface hoar. As strong winds reach less exposed areas, more cohesive slabs have formed over this weak layer at lower elevations.In the south of the region, the remainder of the snowpack is well-settled. Around Bear Pass and in the north of the region, you may find two weak layers of surface hoar buried between 50 and 100 cm. The base of the snowpack may also be composed of weak and sugary faceted snow.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong outflow winds have formed reactive slabs on a variety of aspects and into lower elevations. Expect variable wind slab conditions dependent on exposure to wind and snow available for transport.
Be cautious as you transition into wind affected terrain.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Keep an eye out for reverse loading created by outflow winds.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 27th, 2019 2:00PM

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