The lure of powder slopes and sunny skies will be strong on Sunday. Take a cautious approach towards more aggressive terrain - especially steep, wind-affected terrain.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
We'll see a clearing trend on Sunday and fine weather during the week.Sunday: Clearing in the morning and then dry with some sunny breaks. Light northwesterly winds. Freezing levels 800m.Monday: Sunny with cloudy periods. Freezing levels around 600 m. Light northwesterly winds.Tuesday: Mainly sunny and becoming warm up high. Freezing levels rising to 2000 m. Light northerly winds.
Avalanche Summary
On Saturday, control work with explosives gave mostly Size 1 soft slabs. Over the past three days, ski cutting has consistently produced soft slab avalanches on lee and cross-loaded features, running to size 1.5 in the storm snow at treeline and alpine elevations. On Friday, most slabs triggered were approximately 25cm thick, running on a density change within the recent storm snow.
Snowpack Summary
Approximately 40-60 cm new snow now sits on top of a rain crust (or multiple crusts) that formed during the wet weather at the end of November. Strong (southerly) winds have blown snow around in exposed areas creating drifts and scoured areas. The main areas of concern are lee (northerly) and cross-loaded features in the alpine and treeline elevation bands. Snowpack depths are typically around 150 cm in sheltered treeline locations, although deeper (and shallower) spots certainly exist on account of the strong winds.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.