I know most of you skiers living in the Northwest are probably looking at the forecast and wondering whether this big, wet storm is going to fall as rain or snow and whether or not it is going to be worth taking Monday morning off for a few powder turns. My answer to all of those questions is yes. Yes, we will probably get some rain at the standard ski elevations. Yes, we will probably get a fair amount of snow with this storm, and yes, you should take Monday morning off to get some turns in (Tuesday looks pretty good as well).
I’m asking those same questions so I don’t miss out on a powder day, but I’m also thinking about what this weather pattern will do to our early season snowpack. While rain-turning-to-snow events aren’t uncommon in the Northwest, rain followed by severe cold is. The forecasts are calling for little to no snow after Monday and artic temperatures for most of the week.
The more common rain-turning-to-snow event followed by moderate temperatures usually creates a fairly strong bond between the old and new snow. We like the storms that come in warm and then get colder and colder. That is the classic set-up for a “right side up” snowpack – dense snow on the bottom and light snow on top. The one difference we are going to have with this storm is the dramatic change in temperatures and the lack of snowfall next week.
This scenario will likely set up the perfect conditions for faceting above the rain crust/layer. Cold air temps and a warm, relatively shallow layer of snow above the rain layer will create a dramatic temperature gradient and the snow above the crust will most likely weaken over time. We might have a good bond between the old and new snow initially, but this bond will weaken over time if faceting occurs.
This will likely be our first layer of the winter worth tracking. Take some time this winter to dig down to this layer and have a look. Have fun out there and play it safe.