Avalanche Forecast

Friday night: Clear periods. Light southeast winds.

Saturday: Mainly cloudy. Light east winds. Alpine high temperatures around -14.

Sunday: Mainly sunny, becoming cloudy overnight. Light to moderate southwest winds, increasing overnight. Alpine high temperatures around -12.

Monday: Cloudy with scattered flurries bringing up to 5 cm of new snow, increasing overnight. Moderate to strong southwest winds. Alpine high temperatures around -10.

Over the past few days there have been reports of wind slab, persistent slab (failing on the February 19 surface hoar layer), and deep persistent slab (failing on basal facets) avalanches. This pattern highlights how recent stormy weather has strained multiple weak layers in the snowpack.

Reports from Thursday showed several more wind and storm slab avalanches from size 1-2 (small to large) releasing naturally as well as with skier and snow machine traffic in the Kispiox area. North through east aspects again proved most reactive.

On Wednesday a cornice failure in the same area initiated a size 3 wind slab avalanche on a northeast facing feature at 1600 m that cleared out large timber in the valley. The recent storm snow was sensitive to human triggering, even in low angle terrain, running on the March 1st surface hoar. A few shallow natural wind slabs were also observed in steep terrain.

Human triggered avalanches on the Feb 19 surface hoar layer have been reported almost daily since last Thursday.

Cornice falls have been a common trigger for wind slabs on the slopes below. Last Friday a cornice fall triggered a size 3.5 deep persistent slab on a northeast facing slope at 1800 m.

The Wednesday into Thursday night storm produced 5 to 25 cm of new snow with the deepest accumulations found in the south and accompanied by strong east/southeast wind. Previously, extreme wind from the southwest, west, and northwest has hammered open terrain, scouring some slopes and forming wind slabs on leeward slopes.

Loading from new snow and wind has made several persistent weak layers problematic over the past week. A combination of surface hoar and sun crust layers were buried on February 19 and currently sit 30-60 cm below the surface that seem to be most sensitive to human triggering at treeline elevations. 

A couple of weak layers that formed in January are buried in close proximity to one another 80-140 cm below the surface. Below that, an early season crust/facet layer lurks at the base of the snowpack.

• Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
• Use careful route-finding and stick to moderate slope angles with low consequences.
• The trees are not the safe-haven they normally are at this time. Terrain at treeline is primed for human triggered avalanches.
• Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.