Avalanche Forecast

Moderate - Due to the number of field observations

Wednesday: 3-5 cm of new snow / Strong southwest winds / Freezing level at about 1100mThursday: 2-4 cm / Light and variable winds / Freezing level at about 1100mFriday: Light flurries / Light and variable winds / Freezing level at about 800m

A MIN report from Sunday includes observations of recent Size 2 wind slab in the Hudson Bay area that is suspected to have run naturally on an east aspect. Perhaps more striking is the fact that the party also experienced several whumphs, suspected to be failures at one of our more shallow persistent weak layers. For Wednesday, expect recently formed wind slabs to be reactive to human triggering. Older hard slabs may be more stubborn, but also capable of much wider propagation. A storm focused on the north coast has brought modest new snow accumulations inland along with strong to extreme southwest winds that have promoted the formation of touchy new wind slabs in lee areas. Also keep in mind that a basal weakness continues to drive a low probability/high consequence deep persistent avalanche problem for the region. Very large avalanches remain possible, especially in shallow snowpack areas and as warm temperatures begin to penetrate deeper into the snowpack.

A light snowfall over most of the region has given a thin cover to the widespread wind affected surfaces recently reported in exposed terrain. This includes scoured surfaces, sastrugi, and hard wind slabs as well as a rain crust below about 1400 m. The new snow will contribute to wind slab formation in wind exposed areas while covering faceted surface snow as well as surface hoar in more sheltered areas. Deeper in the snowpack, several buried surface hoar layers can be found between 30-70 cm deep. Recent reports suggest these layers have generally stabilized but isolated weaknesses may still exist, especially where buried surface hoar is still intact. A generally stiff mid pack sits above weak sugary snow near the ground. This basal weakness woke up during the last storm and produced numerous large avalanches which released on the ground. The layer has recently been considered dormant but it may become active once again with sustained warming over the coming days. It may also be possible for a smaller avalanche to 'step down' to this layer.