Regions
Northwest Inland.
New and old slabs are taking their time to bond to underlying layers. Be cautious on southerly aspects when the sun is out -- it could weaken the snow and trigger avalanches.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
MONDAY: Partly cloudy, light southerly winds, alpine temperature -12 C, freezing level 400 m.TUESDAY: Mostly cloudy with light snowfall, accumulation 2 to 5 cm, light to moderate southerly winds, alpine temperature -11 C, freezing level 500 m.WEDNESDAY: Mostly cloudy with light snowfall, accumulation 1 to 3 cm, light southerly winds, alpine temperature -10 C, freezing level 500 m.
Avalanche Summary
On Saturday, a large persistent slab avalanche was reported in the north of the region, failing on the early-March weak layer described in the Snowpack Discussion. It failed on an easterly aspect around treeline. Portions of the avalanche stepped down to sugary facets near the bottom of the snowpack.Otherwise, there was further evidence of the natural cycle that occurred on Friday within the recent storm snow, with storm slab and loose dry avalanches. They were small to large (size 1 to 2.5), on all aspects, and at all elevations.
Snowpack Summary
Expect to find a surface crust on southerly aspects from the weekend’s clear skies.A reactive slab about 50 cm thick has developed from last week’s storm snow. This slab overlies two layers of weak surface hoar, which exist on shaded aspects at high elevations. The slab sits on a melt-freeze crust on all aspects below treeline. The storm snow may still be loose in sheltered and shady locations.Near the bottom of the snowpack, weak and sugary facets are found in shallow, rocky snowpack areas. Storm slabs have stepped down to these facets recently, producing very large avalanches.
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.