Start small and ease your way into terrain on Sunday. Target areas that haven't been exposed to recent winds but keep your guard up around steeper sheltered slopes too.
Lots of new snow has accumulated over the week! In many areas the new snow will be on a positive stabilizing trend, but human triggered avalanches remain a serious concern around steep slopes where the new snow is settling over crust layers as well as in exposed areas where much of this snow has been transported into thick and reactive wind slabs.
Saturday night: Mainly cloudy with easing flurries bringing about 5 cm of new snow. Moderate to strong west or southwest winds, easing into the morning.
Sunday: Mainly cloudy with scattered convective flurries and up to 5 cm of new snow. Light to moderate northwest winds. Alpine high temperatures around -8.
Monday: Cloudy with isolated flurries and a trace of new snow. Light southwest winds. Alpine high temperatures around -7.
Tuesday: Mainly cloudy. Light southeast winds, increasing over the day. Alpine high temperatures around -5.
Friday's reports showed a bit more evidence of the previous day's avalanche cycle, with storm slab avalanches up to size 2.5 (large) seen on all aspects at alpine and treeline elevations. Failure planes were mixed between the most recent storm interface, 20-30 cm deep, and the pre-storm surface about 45 cm deep. New avalanches were reduced, with one report of a ski cut size 1.5 storm slab and several more explosives triggered size 2 releases.
Reports from Thursday's storm showed an uptick in avalanche activity, with numerous mainly small (size 1) storm slabs releasing naturally as well as with skier traffic and ski cutting on steeper slopes in the south of the region. Reactivity appeared limited to the depth of overnight snowfall and also reduced by the end of the day. Further north in Bear Pass, stronger winds and greater overnight snowfall led to more significant wind slab activity, with natural releases generally larger than in the south (size 2-3).
Looking forward, natural avalanche activity is expected to decline quite sharply while the likelihood of human triggered avalanches persists a bit longer. Wind loaded features at higher elevations are primary concerns, however storm slab triggering on steeper slopes in sheltered areas isn't yet out of the question, particularly where recent snow overlies crust.
20-30 cm of new snow accumulated in the region over Friday night and Saturday, bringing snow totals for this week to about 50-80 cm. With settlement, this total is likely closer to 40-60 cm. In exposed areas, the interfaces within and below this storm snow consist mainly of wind-affected surfaces, but also of sun crusts on south-facing slopes that saw sunshine in between storm pulses.
In more sheltered areas, the pre-storm surface, now roughly 40-60 cm deep, is a more varied aspect and elevation-dependant mix of melt-freeze crust (lower elevations), sun crust (sun-exposed slopes), faceted snow and/or surface hoar (shaded aspects).
A thin layer of facets that formed during the January cold snap is now about 120-170 cm below the surface while an early season crust lingers at the base of the snowpack. These layers produced a few large natural avalanches in early February but have more recently been nonreactive.
