New snow and wind have formed touchy storm slabs particulary at upper elevations. With more snow in the forecast, choose moderate, low consequence terrain and carefully monitor how the new snow is bonding.
Weather Forecast
TONIGHT: Snow. Accumulation 10-15 cm. Ridge wind moderate, southwest. Temperature -6. Freezing level 1000 m.FRIDAY: Cloudy, snow. Accumulation 10-15 cm. Ridge wind moderate, southwest. Temperature -3. Freezing level 1100 m.SATURDAY: Cloudy, snow. Accumulation 10-20 cm. Ridge wind moderate, south. Temperature -4. Freezing level 1000 m.SUNDAY: Cloudy, snow. Accumulation 10-20 cm. Ridge wind moderate south. Temperature -6. Freezing level 800 m.
Avalanche Summary
Ski cuts and explosive control work on Thursday produced numerous size 1-1.5, up to size 2, storm slab avalanches, 20-50 cm deep, running far and wide within the recent storm snow.Wednesday ski cutting and explosive control work produced numerous easily triggered size 1 storm slab results up to 40 cm deep running on the January 15th crust.Tuesday, explosive control work and ski cutting produced numerous size 1-1.5 storm slab releases on leeward aspects at treeline and into the alpine, running on the January 15th crust. Expect this activity to increase as more snow and strong winds forecasted for Wednesday and Thursday.Warm alpine temperatures on Sunday produced numerous naturally triggered loose wet and wet slab avalanches mostly in the size 1-1.5 range, and a few up to size 2 on solar aspects.
Snowpack Summary
Above 1600 m elevation, 25-50 cm of new snow overlies the January 15th crust which exists on all aspects and elevations. This crust is thin on northerly aspects and up to 3 cm thick on solar aspects. Below this crust 30-40 cm of moist, well settled snow overlies the January 6th crust which is now buried 40-80 cm below the surface and exists up to about 2000m. Beneath the January 6 crust, the lower snowpack is generally strong and well settled. At lower elevation below treeline the new storm snow is wet and heavy with moist snow below.
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.