Conditions are primed for people triggering avalanches, and wind-loading is expected to result in continued natural avalanche activity. Stick to simple terrain until the fresh snow has a chance to settle and strengthen.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
SATURDAY: Cloudy with flurries bringing another 5-10 cm of fresh snow, moderate to strong southwesterly winds, with freezing levels around 1200 m.SUNDAY: A mix of sun and cloud with isolated light flurries possible, strong southwesterly winds and freezing levels as high as 1600 m.MONDAY: A mix of sun and cloud with isolated light flurries possible, strong southwesterly winds and freezing levels as high as 2000 m.
Avalanche Summary
No new avalanches were reported on Thursday, but initial reports from Friday include several natural storm slab avalanches up to Size 2.5. Expect natural avalanche activity to continue with sustained loading from snow and wind, and fresh storm slabs will remain sensitive to light triggers.
Snowpack Summary
With up to 50 cm of fresh snow on Friday, total snowfall over the past week is around 70 cm with warm temperatures and wind forming very touchy slabs. Weaknesses likely exist within this recent storm, which is also bonding poorly to the previous snow surface from early February that includes old hard wind slabs and crusts as well as faceted snow and surface hoar on sheltered open slopes. The persistent weakness buried mid-January is now down around a metre and consists of buried surface hoar in sheltered areas, and/or widespread faceted old snow. It has generally stabilized but may remain reactive in isolated areas where buried surface hoar is preserved. Another surface hoar/facet weakness buried mid-December can now be found over a metre in shallow snowpack areas. While reactivity at this layer has declined, professionals in the region are still treating it with a great deal of caution.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.