Areas east of the divide have a weaker, thinner, more facetted snowpack, while areas along the divide and further west have a slightly thicker snowpack that is more supportive and a little more confidence inspiring. At lower elevations in all areas the snowpack is still thin with difficult travel and early season hazards present.
Previous SW/W winds created wind slabs in lee features of the alpine. Our main concern is areas where these slabs sit over a weak facetted midpack and are more likely to be triggered. Avalanche activity has tapered, but with increasing winds it is worth paying attention to any wind loading.
Two weak layers near the base of the snowpack (Oct 20 and Nov 9) are producing slab avalanches down about 60-100 cm. Any areas with a stiffer slab over the mid pack facets have the potential to step down to these layers, though the layers have been most reactive in steep, thin, wind affected spots.
No new avalanche observed or reported on Friday. Over the past several days, ski hills have triggered isolated wind slabs and a number of deep persistent avalanches with explosives, but there has been an improving trend.
Old windslabs exist in wind-prone alpine areas. In sheltered locations, 10-40 cm of soft snow sits on a layer of facets, suncrust and isolated surface hoar. Below this the midpack is thin, facetted and weak in eastern areas; and deeper and denser in western areas. Two crust/facet layers exist near the bottom of the snowpack (Nov. 9th and Oct. 20th interfaces). Total snowpack depths at treeline are about 60 cm in eastern areas with up to 100 cm in thicker western areas.
Moderate to strong SW/W winds, treeline temperatures between -8 and -5°C, and only a trace of new snow for Saturday.
An upper trough and system from BC/Washington will move in Saturday. Southwest and west ridgetop winds will increase, west winds through the valleys will dominate and some flurries are expected Saturday, mainly on the western most slopes.
