Avalanche Forecast

Issued: Jan 29th, 2018 5:15PM

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

Avalanche Canada cgarritty, Avalanche Canada

Give all that new snow a bit more time to stabilize before jumping into aggressive terrain. Storm slabs will be especially touchy in areas where high winds have created deep and variable deposits.

Summary

Confidence

Moderate -

Weather Forecast

Tuesday: Mainly cloudy with isolated flurries and a trace to 3 cm of new snow. Up to 15 cm possible in the south of the region. Moderate to strong southwest winds. Freezing level to 1200 metres with alpine high temperatures around -4.Wednesday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light west winds. Alpine high temperatures of -7.Thursday: Cloudy with isolated flurries and a trace of new snow, continuing overnight. Light southwest winds. Freezing level rising to around 1500 metres with alpine high temperatures of -2.

Avalanche Summary

Reports from Saturday and Sunday showed recently formed storm slabs reactive to skier traffic and ski cutting, producing numerous small (Size 1, 20-35 cm deep) storm slab and loose dry releases. Observations from the north of the region on Monday showed especially touchy conditions, with numerous soft storm slabs releasing very easily on terrain over 35 degrees. On Thursday, two natural storm slab avalanches stepped-down to facets at the bottom of the snowpack and resulted in Size 3-3.5 avalanches. They occurred on north and south aspects between 2000 and 2250 m. The potential for these types of deep releases is expected to be generally diminishing with cooling temperatures and tapering snowfall.

Snowpack Summary

Another approximately 20 cm of new snow from Sunday through Monday morning brought recent storm totals to 110-140cm. Rising freezing levels delivered much of this precipitation as rain below about 1300 metres. Where new snow accumulated, continued strong south winds have once again redistributed it into dense storm slabs in lee and cross-loaded features at treeline and above.From 110-140 cm below the surface you'll likely begin find a few crusts that were buried during the first few weeks of January. Due to limited observations, not much is known about the current reactivity of these layers.The lower snowpack includes the more well-documented mid-December crust layer. Persistent slab avalanche activity from late last week suggests that heavy triggers like a large storm slab or cornice release may carry the risk of triggering this layer in isolated terrain - particularly in the north of the region where it has shown prolonged reactivity in snowpack tests.

Problems

Storm Slabs

An icon showing Storm Slabs
Heavy snowfall and intense winds created thick new storm slabs on the surface during the storm. The new snow needs time to form a solid bond to the surface and it may remain reactive to human triggering on Tuesday, particularly at higher elevations.
The new snow will require several days to settle and stabilize.Be aware of the potential for wide propagations due to the presence of hard windslabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Cornices

An icon showing Cornices
Heavy snowfall and and high winds have been building fragile new cornice growth.
Give cornices a wide berth when traveling on or below ridgesFalling cornices may trigger large avalanches on slopes below.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Valid until: Jan 30th, 2018 2:00PM