Reported Tuesday, December 29, 2009 at 5:15 AM
The danger is MODERATE on all aspects and elevations.
Avalanche Problem #1
The avalanche danger is MODERATE which means that it still remains possible to trigger an avalanche today. Deep slab instabilities are still lingering out there and may be triggered from areas of shallow or weak snow. If triggered, deep slab avalanches have the potential to propagate large distances and be destructive.
Avalanche Problem #2
Last week's strong northwest wind has created shallow wind slabs on lee and cross-loaded aspects at all elevations. These slabs may be reactive to skier triggering but have limited potential to injure or bury a backcountry traveler due to their small size.
In the Backcountry
Not much has changed in the backcountry since yesterday; our snowpack still remains complex and variable. Warmer temperatures have helped with the bonding of shallow wind slabs, but lee and cross-loaded slopes may still have shallow unstable slabs resting on weak surface forms. Our cohesive mid-pack remains a slab resting on a weak faceted base and a reported skier triggered avalanche from Marble this weekend indicates that deep slab instabilities still exist. The skier triggered a large avalanche above tree line on a northeast aspect on a slope that already had several tracks in it. The avalanche was triggered from an area of shallow snow and this serves as a reminder that our mid-pack is variable in depth and strength across terrain. Southerly slopes have a semi-supportive sun crust with facets above and below the crust. It has been almost two weeks since our last significant snowfall and many repeated cold and clear nights have created widespread surface hoar and surface facets. Both of these persistent weak layers may be reactive after this week’s storm.