Another round of snowfall is forecasted to produce up to a foot of new snow near the coast with about half as much expected for Thompson Pass.  Temperatures have been rising overnight and are expected to go above the freezing mark below 1000′ during the day for coastal locations.  The amount of new snow we are expecting along with rising temperatures will temporarily elevate the avalanche hazard to considerable in the Maritime zone.  Watch for signs of instability such as shooting cracks and collapsing that would indicate unstable snow at the surface.  Hand shear tests and small test slopes are a quick easy way to test the sensitivity of new snow at the surface.

 The intermountain and continental zones are not expecting enough snow to elevate the hazard in those areas.  The hazard will remain moderate there unless more than the forecasted 4-8 inches of snow accumulates.  

Wind slabs that were found to be reactive on 2/9 are expected to be gaining strength and the heavy snow load from last week has been observed in multiple locations to be well bonded with the snowpack except below 2500′ in the Maritime climate zone (see persistent slab problem below).  

Faceting at the surface was not observed during the brief period of clear weather 2/9-10.  

Up to a foot of new snow and increasing temperatures will put additional stress on a decomposing rain crust that exists below 2500′ that has recently showed signs of instability near the coast.  The layer exists in all three forecast zones but has only been found to be a concern in the Maritime zone,  this includes Keystone Canyon.  This rain crust has lost strength since it has formed and has created a weak layer.  It will be possible for the 1/25 rain crust to act as a failure plane in steep terrain at low elevations.  

Watching for signs of instability such as shooting cracks and collapsing.  Digging snowpits to asses stability in the area you choose to travel is a good idea if choosing to travel in steep terrain at low elevations.

Weak snow continues to exist near the base of our snowpack in all three climate zones.  This weak snow has recently been under increasing pressure as heavy snowfall and strong winds occurred 2/5-7.  The last recorded avalanche activity at this layer occurred during the 1/23-25 storm on Nicks Buttress / ~3500’/ north aspect (see avalanche activity section).  The amount of snow and wind our area just received was significant, and was a great strength test of weak snow near the base of our snowpack.  No avalanches have been observed that failed or stepped down to this layer during the latest storm.  Human triggered avalanches are currently unlikely to occur that fail on weak snow near the base of our snowpack.

Faceted snow near the ground has been found to vary significantly from place to place.  In most locations this snow has been found to be rounding (gaining strength) and unreactive in stability tests.  In thin areas of the snowpack these facets are significantly more developed.  The most likely places to affect weak snow near the ground will be in areas where the snowpack is thin.

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, that could act as a trigger point.

Depth hoar from Nicks Buttress ~4000′ North aspect 1/31.