Watch out for new wind slabs and soft slabs at higher elevations.
Confidence
Moderate - Due to the number of field observations on Monday
Weather Forecast
We have a return to high pressure and arctic outflow conditions until Thursday evening.TUESDAY: Clearing around noon, moderate northeast winds (25-40 Km/hr), alpine temperatures around -12 Celcius.WEDNESDAY: Sunny with light northerly winds (10-20 Km/hr). Alpine high temperatures near -12 Celcius. THURSDAY: Sunny with clouds developing in the late afternoon. Light westerly winds (10-20 Km/hr). Alpine high temperatures near -11 Celcius.
Avalanche Summary
A widespread soft slab cycle (to Size 1.5) was triggered with explosives on Monday. No new natural avalanches were observed.
Snowpack Summary
New snow from Sunday night totalled 15 cm near Whistler while 25-30 cm fell in the upper Callaghan / Powder mountain area. Widespread touchy soft slab avalanches to Size 1.5 occurred on lee slopes with explosives control. The new snow from Sunday night and also last Friday is bonding fairly well to a variable surface consisting of a mix of soft wind slabs, hard wind slabs, sastrugi, faceted snow, and even some surface hoar. Lingering wind and soft slabs are the primary weakness of concern in the current snowpack. Last week's winds reverse loaded many terrain features and formed stubborn wind slabs on a surprising range of aspects. The Boxing Day interface can be found up to 100 cm deep and consists of wind packed snow, faceted (sugary) snow, or surface hoar. Recent observations suggest the overlying snow is generally well bonded to this interface. Snowpack layers below this interface are also generally well bonded.
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.