North Columbia

Convective spring-like weather may bring localized higher snowfall amounts. Moderate winds continue to build reactive wind slabs at higher elevations on the leeward side of terrain features.

Tuesday: Unsettled conditions and convective air could bring 5-10 cm of new snow with mostly cloudy skies. Ridgetop winds will be moderate from the SW and freezing levels near 1500 m. Wednesday: Snow amounts 5-10 cm. Ridgetop winds light-moderate from the South and freezing levels near 1600 m.Thursday: Cloudy with possible sunny breaks. Ridgetop winds light from the SW and freezing levels near 1500m.

Moderate - Intensity of incoming weather systems is uncertain

On Sunday, natural slab avalanches were observed up to size 2.5 mostly from northeasterly aspects above 2300 m and skier controlled smaller wind and storm slabs up to size 1.5 continue to be easily triggered. Cornices are large and fragile and when they fail they continue to trigger large slab avalanches from the slopes below. One of the cornice failures produced a size 3.5 avalanche which ran from a northerly aspect for 1500 m. The recent storm snow is expected to be reactive at higher elevations, especially in wind loaded terrain and on steep convex features. Cornices are large and may become weak with daytime warming or during stormy periods. We are in a low probability, high consequence scenario for persistent slab avalanches failing on deep buried weak layers. Click here for more details. Check out the new Forecasters blog here.

20-50 cm of snow has now accumulated over the past week which overlies a rain crust below around 2000 m or a sun crust on solar aspects at higher elevations. Alpine wind has recently been strong mainly from south through west directions and has loaded leeward slopes in exposed terrain at treeline and in the alpine. Large, fragile cornices are also reported in the alpine. At lower elevations, there may be multiple crust layers in the upper snowpack which are now generally well bonded and stable. At higher elevations, the February weak layers are down 120-150 cm and woke up during last week's storm with many avalanches stepping down. The deep mid-December facet layer and November rain crust both still linger near the bottom of the snowpack and a few avalanches and cornice falls also stepped down to these layers last week resulting in some very large full depth avalanches.