Avalanche Forecast

Fair - Timing, track, or intensity of incoming weather system is uncertain

Unsettled conditions for the interior regions on Wednesday and Thursday as the ridge of arctic air retreats. Seasonal conditions should return by Thursday as a low pressure system will move into the interior from the coastWednesday: Light snow flurries, treeline temperatures -5 to -10C, light to moderate SW alpine winds Thursday: Light snowfall, treeline temperatures around -5C, light to moderate SW alpine winds.Friday: Light snowfall, and a return to more seasonal valley temperatures, with treeline temperatures in the -5 range.

Low density HST has been reported sloughing in steep terrain on the Dec 8th surface hoar and/or facets. On Sunday two natural wind slab avalanches were reported around Revelstoke: a size 1.5 on a steep SE aspect at 2000m and a size 2.5 on a N aspect. Also reported in the area was a size 2 skier triggered persistent slab avalanche releasing on the late-Nov interface on a north aspect 40 degree slope at 1900m.Two ski cut avalanches reported on Saturday around Revelstoke. One size 1.5 storm slab on a NE aspect and one size 1 wind slab on a SW aspect at treeline.At present, the low density new snow does not present a significant problem, unless a skier or rider were carried into a terrain trap.  It may be possible, however, to initiate a larger avalanche on a deeply buried instability.  The possibility of large destructive avalanches still exists in some areas.

Snowpack depths are typically 100-140 cm at treeline elevation. The upper snowpack (up to ~40cm) has undergone faceting during the recent cold temperatures. Surface hoar has also formed in some locations and is now buried by the last two days snowfall.The old storm snow (~30-60cm) overlies the late-November interface which typically consists of sun crusts on steep south facing slopes and surface hoar in sheltered areas. These weak layers are expected to be persistent, although in many areas the upper slab is not yet stiff enough for slab avalanches. When temperatures rise, and we get additional snow, expect this interface to become more of a problem. Strong NE winds after the storm caused reverse loading and wind slab formation on SE through W aspects in wind exposed areas. Lower snowpack layers include a surface hoar layer roughly 60cm above the ground and an early season rain crust at the base of the snowpack. These layers have been inactive but residual risk of large, destructive avalanches exists, especially in areas with a thinner snowpack. The October crust can be found in the alpine on north aspects and the early November surface hoar is isolated within the region.