There is a lot of uncertainty with the reactivity of the buried surface hoar layer down 40-80 cm. Human triggered avalanches are more likely at treeline and sheltered locations in the alpine where this weak layer exists. New forecaster blog
HERE.Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Mostly cloudy skies, cooling temperatures and dry conditions moving into the weekend. SATURDAY: Mostly cloudy with a trace of new snow/ alpine temperatures near -7/ generally light winds from the northeast/ freezing level 900 mSUNDAY: Cloudy/ alpine temperatures near -9/ ridgetop winds light from the northeast/ freezing levels 800 mMONDAY: Mix of sun and cloud with isolated flurries/ alpine temperatures -12/ ridgetop winds light from the northeast/ freezing levels valley bottom
Avalanche Summary
Natural avalanche activity has tapered off but human triggered avalanches remain possible, especially in places where a buried weak layer exists. The most significant report we received on Friday was a persistent slab avalanche that was triggered by explosives. This avalanche was a size 2.5 from a northeast aspect in an upper alpine bowl. The avalanche initiated from a shallow, rocky spot with good propagation. We suspect this avalanche failed on the buried crust at the base of the snowpack. This avalanche character is very similar to the human triggered size 3 mentioned below.Last Saturday, a human triggered size 3 avalanche was reported in the region. This avalanche likely ran on the October crust, as it was reported as a full depth avalanche. Two reports on this avalanche can be found on the
Mountain Information Network. Snowpack Summary
The storm that arrived earlier this week distributed 40-80 cm of new snow by Wednesday morning with the higher accumulations in the Monashee Mountains. This recent snow sits on two layers of feathery surface hoar that are approximately buried 15 cm apart. One or both of these may be associated with a crust on south aspects. The surface hoar is mostly found at treeline, but it may be found in sheltered alpine areas.At the base of the snowpack is a crust that formed near the end of October. This crust is associated with sugary weak faceted crystals and has shown some reactivity in the South Columbia region. Suspect slopes and terrain are open bowls that host a rocky thin to thick snowpack in the alpine or upper treeline. Snowpack depths taper quickly with elevation, many areas have over 200 cm in the alpine, between 100-170 cm at treeline, and 10-100 cm below treeline.Check out the
FORECASTER BLOG as it will express our uncertainties with the current snowpack in this region
swerner,
Avalanche Canada
