A significant storm is expected to raise avalanche danger to high for Wednesday.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Wednesday
Weather Forecast
Tonight: 10-20 cm new snow expected. Moderate easterly winds.Wednesday: a further 10-20 cm new snow expected. Moderate northeasterly winds. Treeline temperatures around -8C.Thursday: Mostly dry during the day. Moderate northwesterly winds. Treeline temperatures around -10C.Friday: Light snow, 2-5 cm. Light easterly winds. Treeline temperatures around -12C.
Avalanche Summary
On Monday, a natural and explosive triggered avalanche cycle was reported in the Lizard Range up to size 2.5 or 3. On Tuesday, smaller (size 1.5) avalanches were readily triggered by ski cutting and explosive avalanche control.
Snowpack Summary
50-60 cm new snow now rests on a variety of old surfaces. These old surfaces include crusts on south through west facing slopes, wind-scoured slopes and, in sheltered terrain at and below treeline, large feathery surface hoar crystals. Lower in the snowpack, you should be able to find a hard crust that was buried near the end of November. This crust is approximately 30cm thick and extends from 1600m to mountain top on all aspects. Average snowpack depths at treeline in the region range from 90 to 130cm.
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.