Triggering wind slab avalanches is possible in steep open terrain. Seek out low density new snow that was sheltered from recent winds.
Expect to find increasingly deep and potentially reactive wind slabs as you gain elevation.This problem is likely most pronounced on the east slopes of the region.
TUESDAY NIGHT: Mostly cloudy, moderate to strong wind from the northwest, alpine temperatures drop to -15 C.
WEDNESDAY: A mix of sun and cloud, light wind from the west, alpine high temperatures around -8 C.
THURSDAY: Mainly cloudy. Light to moderate west winds. Alpine high temperatures around -5 C.
FRIDAY: Mix of sun and cloud with storm approaching in the evening, light wind, alpine high temperatures around -8 C.
Avalanche activity has quieted down in the wake of Saturday's storm. The storm resulted in several large (size 2-2.5) slab avalanches across the region including the eastern slopes as well as in the Elk Valley (see this MIN report). The avalanches in the Elk Valley appear to have run on weak layers in the bottom of the snowpack and released at both treeline and alpine elevations. These avalanche look similar to the deep persistent slabs reported in the same area on January 16 in this MIN report, suggesting this problem will continue to resurface during stormy periods.
Variability in surface conditions is likely to be found in the region. In the Elk Valley and further west, an estimated 5-10 cm of snow sits above a solid new melt freeze crust which has capped the snowpack below about 2100 m. On the eastern slopes of the range roughly 20-30 cm of snow fell at the end of Saturday's storm and likely sits above a similar crust. In the high alpine across the region recent snow has been heavily impacted by strong to extreme wind from the southwest.
A well consolidated mid-pack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. While there has been little in the way of avalanche activity on this layer recently, it may be possible for a large load to trigger it in a shallow, rocky start zone.
