Recent snowfall and wind have heightened avalanche danger in the region. Make conservative decisions and wait for the snowpack to stabilize.
Weather Forecast
Up to another 5cm of new snow is forecast to fall in the South Columbia mountains by Sunday evening as light winds shift to the west. Freezing levels will begin a downward trend on Monday. Only trace amounts of new snow are expected for Monday while Tuesday will see cloud cover decreasing and winds shifting to the northwest.
Avalanche Summary
Stormy weather prevented observations at alpine elevations, but new snow was observed sluffing up to size 1 at treeline and below on Saturday, in addition to skier triggered size 1 and natural size 2+ avalanches reported in Rogers Pass on Saturday. Explosives control in the Revelstoke area on Friday also yielded numerous size 2 results with slab thickness reaching up to 80cm in depth. Danger from storm slab avalanche activity is expected to persist while new snow undergoes settlement.
Snowpack Summary
Up to 25 cm of new snow fell on Saturday under moderate to strong southerly winds. This new snow now covers the already touchy storm slabs that existed in exposed areas at treeline and above. On solar aspects these slabs have been reactive above a sun/temperature crust which formed on November 22 and can be found 30-50cm deep in the snowpack. The thick, widespread November 13 crust now lies up to a metre below the surface. Below this crust the mid and lower snowpack are well consolidated, with moist snow present at treeline and below. Isothermal snow can be found at the base of the snowpack.
Problems
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.