Regions
Northwest Coastal.
Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
Tuesday: New snow accumulations up to 35cm overnight Monday throughout the day on Tuesday. Ridgetop winds 45-70km/hr from the West. Freezing levels near 1000m. Wednesday: Snow amounts 10-15cm. Ridgetop winds 45-55km/hr from the NW. Treeline temperatures near -6. Thursday: Mainly dry. Freezing levels will lower to valley bottom in the morning, then spike near 400m in the afternoon.
Avalanche Summary
Reports of natural sluffing on steep terrain features. One size 1 skier triggered avalanche was reported on Sunday. This occurred on a SW aspect @ 1800m from a convex , wind loaded feature. With forecast wind and snow, avalanche activity may increase.
Snowpack Summary
The last week has seen dribs and drabs of snowfall with light winds in most areas. The recently fallen snow sits over a strong melt freeze crust that exists below 1000m on all aspects and over wind-pressed powder on shaded alpine features. Sandwiched between the newer snow and the aforementioned older surfaces may be a buried surface hoar layer at treeline and below. This surface hoar layer seems most prevalent in protected inland areas. Where it exists, we expect to see gradually increasing reactivity in the surface hoar interface with loading and slab development forecast for this week. Check out our Forecaster's Blog for some insight on incremental loading. The mid and lower snowpack is generally well settled and strong.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
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.