Avalanche Forecast

Issued: Feb 15th, 2019 5:02PM

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

Avalanche Canada jfloyer, Avalanche Canada

Until recently, this region was a hotspot for avalanche activity on two persistent weak layers within the snowpack. Despite the moderate hazard, a cautious approach to backcountry travel is recommended.

Summary

Confidence

High -

Weather Forecast

FRIDAY NIGHT: Around 5 cm of low density snow expected. Mostly light winds.SATURDAY: 2-4 cm new snow. Treeline temperatures around -8C. Light northeasterly winds.SUNDAY: Flurries. Treeline temperatures around -10C. Light northeasterly winds.MONDAY: Dry, with some clear spells. Treeline temperatures around -12C. Moderate northwesterly winds.

Avalanche Summary

On Wednesday and Thursday a few size 1-1.5 wind slab avalanches were triggered naturally and by skiers mostly in the alpine on a variety of aspects. Persistent slab avalanches have tapered off, with three events noted on northeast aspects between 1200 and 1900 m from Monday and Tuesday this week but none reported on Wednesday or Thursday. However, I'd remain leery of the mid- and late-January weak layers especially at treeline elevations.

Snowpack Summary

10-15 cm of recent low density snow sitting on the surface has been blown around by strong northeasterly winds, creating reverse-loading on some slopes. There are two prominent, touchy weak layers in the snowpack that have been responsible for a several dangerous avalanches in the past 2 weeks. The upper layer was buried at the end of January and lies approximately 40 cm below the surface. The lower one was buried mid-January and lies approximately 75 cm below the surface. Both comprise a mix of surface hoar and facets and may lie on top of a sun crust on southerly aspects. Both layers are potentially reactive and in any given location, one or both could potentially exist in the snowpack. Wide propagation has been noted, meaning avalanches have the potential to be large (up to size 3). These weak layers are most prevalent at treeline and below, but may also be found in sheltered areas in the alpine.Average snow depths are approximately 300 cm. Very sporadically, failures have occurred near the base of the snowpack in or close to this region. These releases have almost all been from high alpine areas, possibly triggered close to rocky features.

Problems

Persistent Slabs

An icon showing Persistent Slabs
There are two persistent weak layers in the snowpack, buried approximately 40 cm and 75 cm below the surface. Activity is most pronounced at treeline elevations.
Avoid convexities as well as steep, open and/or sparsely treed slopes at and below treeline.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Any steep opening in the trees should be treated as suspect.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

An icon showing Wind Slabs
Wind slabs have been reported on all aspects in exposed areas. Wind slabs at treeline elevations have the potential to step down to a persistent weak layer resulting in large avalanches.
Wind from a variety of directions has formed wind slabs in unusual locations at and above treeline.If triggered, wind slabs may step down to deeper layers and result in even larger avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 16th, 2019 2:00PM