Heads up this weekend for a significant storm, bringing new snow, high winds and elevated avalanche danger.
Confidence
Poor - Due to the number of field observations
Weather Forecast
A significant storm is approaching this region for the weekend. Expect snow and high winds.Friday: Flurries, turning to light precipitation at the end of the day. Strong westerly ridgetop winds. Freezing level around 800 m.Saturday:10-15 cm new snow. Strong westerly winds continue. Freezing level around 800 m.Sunday: 10-25 cm new snow. Some areas may see significant snowfall rates. Strong SW winds. Freezing level lowering to surface.
Avalanche Summary
No new avalanches have been reported.
Snowpack Summary
Light snow has buried surface hoar that has grown this week, which is likely most prevalent on shady slopes at upper treeline and lower alpine elevations. On southern aspects, a expect a thinly buried crust. Snowpack depths at treeline elevations are about a metre, with some wind loaded pockets reported to be near 2 metres deep. Below the recent new snow, the upper snowpack is fairly well settled. A buried surface hoar layer may exist around 60 cm down but seems to be spotty, and drainage specific. Deeper in the snowpack near the base is a melt-freeze / rain crust that formed in October. This is generally found from 80-160 cm down near the base of the snowpack. This layer was reported to be down about 90 cm and "a hard ice crust" on the West slope of the Caribous near Wells Gray Park. Snow pack depths are low for this time of year, with snow pillow data showing that most areas are below average and some are near minimum since data has been collected.
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.