Today’s (Friday) Rain and the Weekend outlook

This is a quick post in prelude to the afternoon “Weekend Update” which we’ll post between 3 and 6pm. The weather maker moving through the area today will give us up to 0.45-.5″ of total melt water, primarily rain in the mountains.  Currently the valleys and the summits are colder than avalanche terrain at the mid elevations, which have been above freezing for many hours already. There is a chance for a period of heavy rain this morning with even a clap or two of thunder.  As this system moves through a cold front will usher in dry cold air.  The weekend should offer fairly clear skies, albeit a bit cool.  As for surface conditions and the existing cold snow that exists…..well…we need to wait a bit to see how much rain we get but generally we’re thinking this:

  1. Rain today will increase avalanche danger quickly with natural wet slab avalanche potential.
  2. The cold front, falling into the teens F on the summits, will begin locking up the snow pack from the surface down decreasing the avalanche danger, but creating slick surface conditions.
  3. Saturday morning will start cold with icy surfaces, but sun and and very light winds from the north will allow for softening on S and SE faces.
  4. The avalanche danger over the weekend will depend a lot on the amount of rain we get today, how deeply free water can percolate into the snowpack, and in part how much warming we get on Saturday and Sunday.  We will be in a general decreasing avalanche danger but we may have some aspects higher than others (Moderate and Low). Again depends on rain today and how hard a “reset button” our snow pack goes through.  See Today’s avalanche advisory discussing the Considerable rating for Friday, don’t forget to check the weekend update later today, and certainly the Saturday Avalanche advisory in the morning.  Chris