Falling cornices have been reported in multiple locations on 2/22.  These have produced D3  (very large) avalanches in multiple locations including The Books , PK 7601 (Tsaina/ Tonsina Pass) and Woodworth area.  Cornices have been observed and reported as being larger than normal and poorly attached.  Cracks on ridge tops showing cornices separating from ridge lines have been observed.  Cornices will be growing in size with an anticipated north outflow wind event beginning on 2/25.

Cornices are an objective mountain hazard that should always be a concern.  Although, recent activity strongly shows that we need to keep an extra cautious approach to avoiding overhead exposure to cornices.  Avoid traveling below or on top of cornices.  The avalanches that cornice fall has recently produced are unsurvivable events.

North winds that were created on 2/20 have been found to be gaining strength and at this point are unlikely to be affected by human triggers.  Strong south winds and light snowfall on 2/23 may have created shallow instabilities (less than 1 foot) in specific locations.  The distribution and sensitivity of new wind/storm slabs will be dependent upon storm totals from 2/23.  Accumulation appears to have been minimal at this point with 3-4 inches on Thompson Pass with similar amounts in Valdez reported, although higher amounts are possible at upper elevations/ different locations.  In previously wind sheltered terrain surface hoar up to 1 cm was previously observed.  This has now been buried by the most recent snowfall in specific – isolated locations.  It is unlikely at this point that we have received enough new snow to create a sufficient slab atop this weak layer to create a problem.  But we can’t rule out the possibility since storm total amounts are unclear at upper elevations at this point.  To asses the stability today pay attention to new snow amounts and the amount of wind redistribution that has occurred at the surface. Test slopes and hand shear pits are a good quick way to gather information on how well snow is bonded at the surface.  In areas where there is a foot or more of new snow the avalanche hazard will be Considerable.

Natural avalanche activity caused by cornice fall reported on 2/22 indicates that a persistent weak layer in the mid snowpack exists at upper elevations. The 1/14 buried surface hoar layer is likely the weak layer involved, although this has not been confirmed.  This layer has been quiet for over three weeks, but recent activity shows that large triggers can still produce avalanches.  Human triggered avalanches remain unlikely at this layer although large groups, cornice/ice fall, or large groups may be able to still produce avalanches at this layer. 

Rain crusts that formed in late January have promoted faceting in the mid snowpack at low elevations (below 2500′).  No natural or human triggered avalanches have been reported or observed that failed at this layer, although poor structure exists and stability tests have produced propagation at this interface.  

As time goes on and this layer becomes deeper in the snowpack with additional snowfall, the likelihood of human triggers will be decreasing.  It is still worth investigating this layer if traveling in steep/ consequential terrain at low elevations.  Areas where the snowpack is thin will be the most susceptible to failures at this plane.

Weak snow created by early season cold temps, dry conditions and strong north winds have showed poor structure near the base of the snowpack.  This weak snow has been dormant through the majority of the season with human triggered avalanches being unlikely at this layer.  As the sun has come out the last few days several very large natural avalanches have occurred with cornice and ice falls being the triggers.  Human triggers remain unlikely at this layer, although these events show that large triggers can affect this weak snow.  Cornice fall will be the most likely trigger to affect this weak snow, although it is possible that a large group could have the same affect.  Avoid overhead exposure to cornices.

In most location facets near the ground have been found to be rounding and unreactive in stability tests.  In thin areas of the snowpack basal facets have been found to be more developed.  If you find it is possible to push a ski pole to the ground in areas you travel, assume that a weak faceted snowpack exists in that location. These areas could act as a trigger point.