Ongoing winds continue to load storm slabs. Extra caution is required when transitioning into exposed and wind-loaded terrain.
Weather Forecast
Snowy conditions today with 5cm of accumulation. Cool temperatures with an alpine high of -10.0 and westerly winds gusting to 45km/h. A weak low pressure system spreads isolated flurries into late Saturday. On Sunday, cold arctic air replaces the low pressure, with temperatures dipping down to the nether regions of tolerable.
Snowpack Summary
Storm snow remains unsettled with up to 50cm of ski penetration. Ongoing southerly winds have created reactive pockets of wind slab in exposed areas. On solar aspects, a well developed crust is buried 40cm. Persistent weak layers from January and December are now buried 150-200cm.
Avalanche Summary
A natural avalanche cycle occurred yesterday, corresponding to loading from strong daytime winds. A size 3.0 and four size 2-2.5 natural avalanches were recorded in the highway corridor east of Rogers Pass. A size 2.5 was reported in Connaught drainage in the Cheops North 1 slide path that ran to the valley bottom, nearly hitting the skin track.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.