Lizard-Flathead

It's uncertain how the snowpack will respond to a warm, wet, windy storm. It's time to be extra conservative with your terrain choices.

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

TUESDAY: Wet flurries with 5-15 cm of snow, strong southwest winds, freezing level around 1900 m.WEDNESDAY: Periods of snow and rain with 10-20 cm of snow above 1900 m and strong southwest winds.THURSDAY: Morning flurries then clearing in the afternoon with freezing level dropping to 1000 m, strong southwest winds.

Natural storm slabs in the size 1.5-2.5 range have been reported in steep alpine terrain on a daily basis with the ongoing snowfall. Explosive cornice control on Sunday triggered numerous storm slabs and two deeper slabs that potentially failed on the February interface about 1 metre deep. Ski cutting produced several size 1.5-2 avalanches on wind loaded terrain features. Last Wednesday, a size 3.5 avalanche on Mt. Hosmer was a sign the deep persistent slab problem still exists as well.Expect a wide range of avalanche problems during the next few days of warm weather. Expect fresh storm and wind slabs at higher elevations, touchy cornices at ridgetops, unstable wet snow at lower elevations, and the possibility of large persistent slab avalanches on the February interface and basal facets.

A warm wet storm will form fresh slabs at higher elevations while rain with fall below treeline. Strong winds will load lee features and continue to grow large cornices on alpine ridges. March has delivered regular storms with roughly 80-120 cm of snow sitting above crust and facet interfaces from February. Little is known about the distribution and reactivity of these interfaces. Isolated basal facets still exist in shallow snowpack areas and can produce destructive full-depth avalanches. Possible triggers for these deeper weak layers include cornice falls, rapid warming, or strong solar radiation.