The trees are NOT a safe haven right now as a persistent weak layer at lower elevations is sensitive to human triggers. Increasing winds Saturday may form touchy wind slabs in the alpine too.
Confidence
Low - Due to the number of field observations
Weather Forecast
We've reached the end of the high impact storm train. A rather mundane system drifts into the region Saturday night and then we're looking at high pressure for at least a few days. SATURDAY: Trace of snow during the day. Freezing level near valley bottom. Winds expected to be light W/SW for most of the day, increasing to moderate SW in the afternoon. SATURDAY NIGHT: Freezing level at valley bottom, moderate to strong SW winds, 2 to10cm of snow. SUNDAY: Freezing level rising to 500m. Moderate SW winds. 2 to 8cm of snow expected. MONDAY: No snow expected. Freezing level at valley bottom. Light to moderate NW winds.
Avalanche Summary
Recent observations have been very limited, but I suspect that recent avalanche activity is far more widespread than the current data set would lead us to believe. On Thursday a large natural avalanche (size 2.5) was observed on a NE facing feature at 2000m.
Snowpack Summary
A string of storms that began on December 2nd has produced 70 - 130cm of storm snow in the Cariboos. You may find a brittle crust about 20 cm below the snow surface as high as 2000m that was formed by rain and warm temperatures last Tuesday. Below all the new snow lies the early December persistent weak layer. This weak layer manifests as an old sun crust on due south facing features in the alpine, large grained surface hoar below 1800m and small facets in isolated pockets. The surface hoar is the major player and it's been most reactive below treeline between 1400 and 1800m. Recent winds out of the southwest have formed wind slabs on lee features that are mainly confined to the alpine, but you may find the odd fresh wind slab at treeline too. The mid and lower portions of the snowpack are thought to be well settled.
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.
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.