Friday was a day of rapid change and increasing avalanche hazard due to intense snowfall and windloading. This trend will continue with wind and heavy snow expected for the weekend. Stick to simple terrain until the new snow has had time to settle.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
TONIGHT: Snow. Accumulation 10-15 cm. Ridge wind moderate, southwest. Temperature -2. Freezing level 800 m.SATURDAY: Snow. Accumulation 25-35 cm. Ridge wind moderate, southwest. Temperature -1. Freezing level 800 m.SUNDAY: Heavy snow. Accumulation 30-50 cm. Ridge wind strong, southwest. Temperature -1. Freezing level 900 m.MONDAY: Snow. Accumulation 5-15 cm. Ridge wind moderate, southwest. Temperature -1. Freezing level 800 m.
Avalanche Summary
On Friday ski cutting produced size 1, storm snow releases on a south-facing, wind loaded feature at treeline. Rapid loading and significant cornice development were also reported on Friday with professionals in the region commenting that conditions were changing dramatically during the day, and avalanche hazard increasing.
Snowpack Summary
Above 1000m about 30 cm of new snow has fallen with as much as 50-60 cm of new snow at higher elevations. This storm snow now covers the January 17th crust and is being redistributed by wind at upper elevations. Below 1000 m, rain has soaked the upper snowpack which consists of 90 cm of wet to moist snow and three deeper crusts (January 10th, January 8th and January 7th). These remain visible but have been unreactive in recent snowpack tests. The snowpack depth at 1000 m is about 160 cm and many early season hazards are still present.
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.