School in Roger's Pass skiing off Mt. Fidelity.
The snowpack in the area is approximately 250cm-300cm and very well settled
with no significant layers in the lower snowpack. On January 16th the
surface hoar was buried by about 15 cm of very low density (20-30 kg/m3)
cold dendrites that mixed right into the predominately needle shaped
surface hoar crystals. This surface was sluffing fast and far but not
slabbing at all except on ridgecrests in the alpine where a thin wind slab
formed on the immediate lee features only.
About 20cm of denser (70-100 kg/m3) fell on the night of the 18th and
morning of the 19th creating an unstable upside down thin soft slab. The
denser snow was failing naturally on all steep rolls and banks but was only
failing at the dense/less dense interface and not digging down to the Jan
16 layer.
As the storm snow settles some more, the Jan 16 layer will likely become
the active layer, but due to the nature of the surface hoar and the way it
was buried, it will probably not be a long-term persistent weakness. It
will definitely require some watching in the short term, however. With the
forecast for a couple of low intensity storms and warming temperatures,
conditions will be ripe for a skier triggerable slab condition.
Brad White
Mountain Guide
_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.