More avalanche control today resulted in many large avalanches, some running to the end of their runouts. Now is a good time to stay out of avalanche terrain!
Weather Forecast
Continued light precip and winds on Thursday until the next storm arrives on Friday/ Saturday. Temperatures look to remain cool throughout. 30-40 cm of snow is forecast over the next 3 days. Winds will increase to strong from the west on Friday.
Snowpack Summary
40-80 cm of snow over the last seven days has overloaded 3 persistent weak layers of surface hoar and facets in the upper half of the snowpack: Jan 16 down 30-50cm; Jan 6 down 40-70cm; and Dec15 down 50-100cm. A major avalanche cycle is ongoing with avalanches running fall path on these layers and some stepping down even deeper.
Avalanche Summary
Natural activity has tapered slightly, but big results with explosives proves that these layers are prime for triggering. Some avalanches ran full path putting dust or debris on roads. Emerald Lake Slide Path ran naturally size 3.5 in the last 2 days to within 100m of the road. Guinness Gully Ice Climb put debris on the road with explosives
Confidence
Due to the number of field observations
Problems
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.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.