Another outflow wind event is taking shape that will likely last through mid day Monday.  Snow available for transport amounts vary fairly significantly across the forecast area, this will affect the depth of new wind slab formation.  Most areas have sufficient loose snow at the surface to form wind slabs on SE-NW aspects in areas being affected by the wind.  Expect to find fresh wind slabs that are 6-18 inches in depth that will be reactive to human triggers.

Another variable factor will be the surface that wind slabs are being deposited on.  These will range from old wind slabs, new snow from 2/23 and a layer of buried surface hoar that exists directly under the 2/23 new snow.  Areas where wind slabs overlies the 2/23 buried surface hoar will be the most sensitive.  Shallow hand pits can help to determine what wind slabs are being deposited on.  Watch for red flags such as shooting cracks, collapsing and recent avalanche activity that would indicate unstable snow at the surface.

Falling cornices have been reported in multiple locations over the last week.  These have produced D3  (very large) avalanches at high elevations of 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 and reported.  Cornices will be growing in size today as a outflow (north) wind event develops.

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.

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 may be able to still produce avalanches at this layer.   The most likely places to encounter this interface to be sensitive will be in thinner snowpacks like what may be found in the Continental zone.

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 in isolated locations.

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 last week 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.