Avalanche Forecast

High - Confidence is due to a stable weather pattern with little change expected.

Tuesday Night: Mostly clear, localized cloud. No new. Light west wind trending to moderate northwest at higher elevations. Freezing level falling to valley bottom. Alpine low around -7 C.

Wednesday: Scattered clouds, possibly clear by the afternoon. No new snow expected. Light northwest wind, trending to extreme at higher elevations. Freezing level at valley bottom overnight, rising to 600 m by the afternoon. Alpine high around -7 C.

Thursday: Mostly sunny. No new snow expected. Light southwest wind trending to strong northwest at higher elevations. Freezing level at valley bottom overnight, rising to 500 m by the afternoon. 

Friday: Scattered clouds. No new snow expected. Light southwest wind trending to strong west at higher elevations. Freezing level at valley bottom overnight, rising to 700 m by the afternoon. 

No new avalanches were reported before 4 pm on Tuesday.

On Monday, professional operations in the north half of the region reported numerous natural windslab avalanches, mostly size 2 to 2.5, with one size 3 reported. These wind slabs were mostly in steep, alpine terrain, and were presumed to be the result of moderate to strong northwest to southwest winds. 

 

On Sunday, a professional operation west of Panorama reported a size 2.5 natural windslab avalanche that appeared to have been triggered by a falling cornice. It was on a south aspect in the alpine.  

On Saturday, west of Invermere, a small, rider triggered avalanche was reported to have failed on the early December persistent weak layer. The snowpack may be shallower in this location, making this layer easier to trigger, but it's a good reminder that this crust/facet combo has not healed. 

New surface hoar is growing on top of 2- 5 cm of fresh snow that fell overnight between Monday and Tuesday. This covers another layer of surface hoar up to 12 mm in sheltered terrain, and a crust on solar aspects. This crust is reported to be thicker (up to 2 cm) and more likely to be present on steep slopes. 

In the northern end of the region, the upper snowpack seems to be mostly wind effected, especially in the alpine. 

This Mountain Information Network post seems to indicate that the surface crust could be thicker and more solid in the south end of the region. 

A couple of thin surface hoar and crust layers exist in the upper 40 cm of the snowpack. These layers have not been producing concerning results in recent snowpack tests.

The most notable layer of concern in the snowpack is a crust that was formed in early December and is now down 90-160 cm. This layer was reactive early last week producing large size 3 avalanches.

Activity has tapered, however, daytime warming, sun, cornice fall, and human triggers from steep, rocky slopes, with a shallow or thin-to-thick snowpack may still be able to trigger this weak layer. 

• In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
• Start on smaller terrain features and gather information before committing to bigger terrain.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
• Avoid terrain traps where the consequence of any avalanche could be serious.