The most likely avalanche problem to encounter within our forecast zone will be wind slab.  The Hamilton storm cycle (3/17-18) provided us with 2-3 feet of new snow above 1000′.  This new snow fell atop very strong wind affected snow in most places along the road corridor.  Good bonding has been observed and reported in multiple locations at the new/old interface.  A density change (weakness) exists within the storm snow, this has been observed to be gaining strength although assessment remains necessary and human triggered avalanches remain possible in steep terrain especially where wind slabs exist.

Light snowfall and moderate to strong east winds are forecasted today that will build fresh wind slabs and add to older wind loads on the lee side of high elevation ridges, terrain features and cross loaded gullies.  Human triggered avalanches are possible 1-3 feet in depth on specific terrain features.  Watch for signs of wind slab at the surface including hard snow over soft and pay attention to red flags such as shooting cracks that would indicate unstable snow.

 The majority of locations in our forecast zone have shown the Hamilton storm snow from 3/17 sits atop very strong wind damaged snow with good bonding observed.  In areas that were more protected from late February-early March north winds, this interface consists of near surface facets.  This difference in interface is important to identify.

 Human triggered avalanches are possible up to 4 feet deep in areas where facets are present at the new/old interface or where storm slab that are deeper than 3 feet exist.  These conditions are not as likely to be found within our forecast zone but have been reported in areas to the southeast of Thompson Pass that received higher storm totals, and in more continental locations where the underlying snowpack is weaker.  Ski pole probing and digging snowpits are good ways to identify what type of interface the recent new snow is sitting on.  Light snowfall and moderate to strong east winds today will be adding weight to persistent slabs.

Other persistent weak layers exist in our mid to lower snowpack.  These are currently unlikely to be affected where very strong wind affected snow exists at the 3/17 interface.

Weak snow exists at the base of our snowpack.  This weak snow is currently unlikely to be affected due to the strength of old wind affected snow at the 3/17 new/old interface.  Depth hoar may become a concern later in the season if our area continues to see major snowfall and the very strong wind damaged at the new/old interface starts to break down and loose strength within the snowpack.  As very hard wind slabs break down within the snowpack a person or machines weight will have a more direct affect on weak layers at the bottom of the snowpack.  In addition,  the increasing intensity of the sun will be putting pressure on deep layers during the heat of the day.