Avalanche Forecast

Issued: Feb 13th, 2019 5:05PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Storm slab avalanches may remain problematic, especially in more extreme terrain. Very little snow is expected Thursday, but if we get surprised by more than 10 cm, loose dry avalanches are likely to follow.

Summary

Confidence

Low - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

The current weather pattern is rather complex, and the weather models are not in agreement. As of Thursday afternoon the models all look to be on the dry side, but this could change rapidly, stay tuned for more details. WEDNESDAY NIGHT: Freezing level at valley bottom, around -10 C in the alpine, light southeast wind, no significant snowfall expected.THURSDAY: Broken cloud cover, freezing level rising to 900 m, light to moderate east/southeast wind, precipitation beginning in the afternoon, 3 to 5 cm expected late in the day. FRIDAY: Broken cloud cover, freezing level around 1000 m, light variable wind, trace of snow possible.SATURDAY: Broken cloud cover, freezing level at valley bottom, light variable wind, trace of snow possible.

Avalanche Summary

Conditions sounded pretty good Wednesday with minor sluffing in most terrain. A size 1.5 slab avalanche was observed on a steep southwest facing line in the Whistler/Blackcomb backcountry in this MIN report.On Tuesday loose dry sluffing was reported from steep terrain at all elevations. Shallow soft wind slabs to size 1 were reported from steep lee terrain features. On Tuesday night an avalanche cycle produced widespread loose dry avalanches to size 1.Over the weekend, small pockets of wind slab were reactive to skier traffic in steep and immediate lee features. Of note is a MIN from the Whistler backcountry reporting wind slabs at lower elevations and in more sheltered terrain than usual (see the MIN here).

Snowpack Summary

10 to 30 cm of low density storm snow has fallen over the last few days with wind generally out of the south. Previous to this most recent storm, the region was hit hard by an extreme wind event featuring winds out of the north and northeast which wreaked havoc on alpine and treeline features. So, the fresh snow rests on heavily wind affected snow and stiff old wind slabs. Due to the scouring and wind-loading, anywhere from 0-100 cm of snow sits on a crust on all aspects below 2000m and solar aspects into the alpine. Above 1800 m, recent cold temperatures have been working to facet and break down the buried crust. In sheltered terrain at and below treeline a layer of weak feathery surface hoar or sugary facets may be identified, but this interface has produced little recent avalanche activity. The remainder of the snowpack is generally well-settled.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs may overlie a crust on south facing features making them more sensitive to human triggering. Carefully evaluate your line for wind slab hazard if you're heading into the alpine.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Use ridges or ribs to avoid pockets of wind loaded snow.Minimize exposure to steep planar south-facing slopes - especially if they see sunshine.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Feb 14th, 2019 2:00PM

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