The weather this weekend is looking intense! Choose your objectives carefully, and minimize your exposure to avalanche terrain when it starts dumping and wind starts howling.
Weather Forecast
A weakening front will continue to give light snow today, but we should have a lull in the weather this afternoon. Expect up to another 10cm today, with moderate to strong SW winds. Another system arrives overnight, bringing heavy snowfall. Up to 30cm are expected by the end of Saturday. On Sunday, heavy snowfall with strong winds are forecast.
Snowpack Summary
A new storm slab is building over top of various potentially weak snow surfaces. Up to 40cm overlies surface hoar, graupel and/or thin sun crusts on steep solar aspects. Last week's storm slab continues to bond, with only resistant planar results in tests. The lower snowpack is facetted but is showing signs of strength more typical for this region.
Avalanche Summary
Yesterday there were several natural avalanches observed east of Rogers Pass. They primarily occurred from steep, wind-loaded features. There were 5 size 2-2.5 avalanches from N aspects and one size 2.0 from a S aspect. Skiers reported sluffing in the top 20cm snow.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
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.
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.
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.