Northwest Coastal

Avalanche hazard is expected to quickly drop with cooling over the weekend but there may still be lingering problems on Saturday. Give the snowpack time to cool down before venturing into complex terrain.

Moderate

A weak frontal system is expected to arrive Friday night bringing moderate southwest winds to the alpine. Freezing levels are forecast to drop to around 1000m by Saturday morning. Cloudy conditions are expected for Saturday morning with light scattered flurries. A mix of sun and cloud is expected for Saturday afternoon with freezing levels around 1500m. Mostly cloudy conditions are forecast for Sunday with light snowfall. Alpine winds are expected to be moderate from the south with afternoon freezing levels around 1300m. Light snowfall is forecast to continue on Monday with moderate southerly winds in the alpine and afternoon freezing levels around 1300m. Forecast precipitation amounts appears to be greatest in the southwest of the region with models currently showing 15-20mm between Sunday morning and Monday evening.

On Thursday, a natural cycle up to size 2.5 was reported throughout the region. Widespread loose sluffing was reported as well as cornice releases and a few large slab avalanches. On Wednesday, numerous slabs up to size 2.5 were reported on solar aspects in the far north of the region. Some of these releases were over 2m deep on old weak layers. In the south, the activity consisted mainly of loose wet avalanches up to size 2.5 and cornice releases up to size 2.5. The cornice releases were not triggering slabs in the southern part of the region. Conditions are expected to improve quickly when the temperatures drop on Saturday but there has been so much heat added to the snowpack over the last few days that some of the deep persistent weak layers may remain reactive for a few days. Once the snow surface develops a widespread supportive crust layer, it will become unlikely to trigger any deep weaknesses. Lingering cornices may remain reactive to human-triggering until there has been substantial cooling.

Over the last couple days, the snow surface has been developing a weak crust overnight which has been quickly breaking down in the morning due to the warm temperatures. With the freezing levels dropping substantially Friday overnight, a more substantial crust is expected to form and is not expected to fully break down on Saturday at higher elevations. If the crust remains supportive, it is expected to cap any deeper weaknesses. The warm temperatures and sun over the last week have woken up deeply buried weak layers within the snowpack. This includes a weak crust/surface hoar layer which was buried down 30-40cm in the north of the region, a widespread crust/facet layer buried in early February down around 1m, a lingering surface hoar layer from January down over a meter, and weak basal facets at the bottom of the snowpack. These old weak layers may still have isolated potential to produce large avalanches over the weekend, especially with a large trigger such as a cornice fall. Once the snowpack has seen substantial cooling, these layers are expected become inactive.