Dangerous avalanche conditions remain as new snow settles and the snowpack adjusts to the new load. Human-triggering potential persists as natural avalanche activity tapers off.
A weak layer found down 80 to 120 cm has been the culprit of recent very large avalanches in the region. This layer may take a few days to adjust to the new snow load. Avoid thin, shallow areas where triggering is more likely.
30 cm of storm snow and winds have built reactive storm slabs. Investigate the bond of new snow to surfaces below before committing to terrain. Be cautious in lee features where winds have redistributed snow into deep cohesive pockets.
On Tuesday, poor visibility kept operators in the area from seeing into higher elevations. Users who head out tomorrow will likely see evidence of a widespread natural avalanche cycle from within the storm.
On Saturday, a very large (size 4) avalanche was reported on Joffre shoulder. It is hard to determine what layer this avalanche failed on however we suspect it to be the weak layer of facets or surface hoar overlying a crust at the base of the snowpack.
20 to 40 cm of storm snow and strong southwest, switching to northwest, winds have built fresh slabs at higher elevations. New snow overlies wind-affected surfaces and a layer of surface hoar in sheltered areas at treeline and below.
A prominent crust varying in thickness is found at treeline and below, 40 to 80 cm down. In some areas, a layer of preserved surface hoar is found just above the crust.
Another weak layer of facets or surface hoar overlying a crust is found at the base of the snowpack down 80 to 120 cm. This is the suspected failure plane for a few large avalanches in the region that occurred on January 6.
Snowpack depths are 100 to 140 cm at treeline and decrease rapidly below.
Tuesday Night
Cloudy with scattered flurries, 2 to 5 cm of snow in most areas, 10 cm local to Cayoosh. Northwest ridgetop winds 10 to 25 km/h. Treeline temperature -9 °C.
Wednesday
Mainly cloudy with isolated flurries, trace amounts of snow. Northwest ridgetop winds 10 to 25 km/h. Treeline temperature -14 °C.
Thursday
Mix of sun and cloud with isolated flurries, trace amounts of snow. Southwest ridgetop winds 20 to 40 km/h. Treeline temperatures drop through the day to -20 °C.
Friday
Sunny skies. Northwest ridgetop winds 10 to 40 km/h. Treeline temperatures -25 °C.
More details can be found in the Mountain Weather Forecast.
