From the NWAC:
SNOWPACK ANALYSIS
Although briefly decreasing winds and snowfall have allowed for a slight danger decrease from the recent avalanche warning situation, significant weak layers remain buried in a continuing scary and quasi-continental snowpack structure. This structure consists of large amounts of recent slightly higher density snow received this past week lying over smaller amounts of lower density snow from last week, all over a weak and increasingly faceted crust formed in early December. This faceting and associated temperature gradients near the crust have now reduced the crust to a mostly decomposed and rather weak granular structure in many areas while allowing for an increasingly poor bond between the crust and the overlying large amounts of recent snow. Additionally, buried weak layers of surface hoar are interspersed with some weaker low density layers above the crust. Finally, in areas where winds and snowfall decreased overnight, some very low density snow and surface hoar has been reported early Friday morning. Obviously this apparently more stable and fluffy snow structure near the surface is masking some very substantial and deeply buried instabilities. As a result, high danger continues above about 5 to 6000 feet in steeper avalanche terrain of the Olympics, Mt Hood area and Washington Cascades near and west of the crest, with a slightly lower but still considerable avalanche danger at lower elevations and along the Cascade east slopes. Back country travelers should exercise significant caution in avalanche terrain with travel not recommended on steeper wind loaded slopes at higher elevations.
Field reports from many areas continue to indicate a dangerous snowpack structure, with both human and explosive triggered large slabs being reported during the past few days. Slab depths have ranged from a few feet up to 6-7 feet, with most larger slides releasing on either the decomposed old crust or the ground. Good fracture propagation has been noted as well as sympathetic releases and resulting avalanches quickly running full path and beyond. Also, many reports of shooting cracks and sudden snowpack settlement (whomping) continue, indicating significant collapse of overlying slabs on one or more buried weak layers. As a result of all of these weather and snowpack conditions, back country travel in avalanche terrain is still not recommended at higher elevations on Friday. All back country travelers, whether their mode of travel is by ski, snowboard, snowmobile or snowshoe, are urged to confine travel to more gentle and/or tree covered terrain until the recent large amounts of new snow have had a chance to further settle and stabilize.
It should also be noted that the snowshoer who triggered and was caught by a slab avalanche near Edith Basin above Paradise on Mt Rainier on Tuesday remains missing; hopefully better weather will aid searching efforts today.
It is important to re-emphasize that although a recent decrease in winds in some areas may make the current new snow surface very attractive, this surface is masking a variety of buried weaknesses which may need only a little added stress to release. While slow snowpack stabilization should occur Friday, several episodes of heavy loading over the weekend should bring further significant danger increases mid-late Saturday and again mid-late Sunday. Although most avalanche activity should involve only the most recently deposited snow releasing on lower density snow or some surface hoar, this weather should maintain the potential for some very large slab slides that may still involve all of the recent snow down to the old early December crust, especially in areas not experiencing recent avalanche activity.
