Cracked Ice

At road level there was 30 cms of dry uncohesive snow on top of the 12/10 rain crust that was still very supportable on skis.  10 cms of this fell in the last 24 hours.  Buried surface Hoar was identified below the new snow that fell in the last 24 hours and will be referred to as the 12/22 BSH layer (buried surface hoar).  Shooting cracks were common below brushline 10-15 cms deep but were very limited in length and presented as  1-2 foot circles radiating from skis on the uphill on any kind of steeper terrain roll.  The short distance of crack propagation was likely due to the lack of cohesion with the overlying slab.  

Above brushline cracking disappeared while new snow depths increased to 20-30 cms.    At 3200' on a North aspect pit results produced ECTN 16 down 30 cms on 12/22 BSH up to 2 cms in size.  The 12/10 rain crust was still present but was breaking down and could not support a person on skis.  The grains in the 12/10 layer consisted of 1-2mm meltform clusters that were faceting.  Height of snowpack was 135 cms with moist facets(could make a snowball)  at the base of the snowpack.  12/10 and 12/5 raincrust were only separated by 10 cms.  November wind board was directly below 12/5 rain crust and only 5 cms thick and 1F+ in hardness with 1mm rounds that were faceting below.  

 

 

Cracking was observed below brush line 15 cms deep. Cracks were short in distance due to the slab above having very little cohesion. Buried Surface Hoar existed at the failure plane.