Monday, January 13, 2014

Evolution of an Eastern Snowpack

We've had some downtime here in upstate NY and are using the time to analyze some of the data we've collected in the last several weeks over the Tug Hill Plateau.  I wanted to share a very interesting graph that shows the dramatic impact that the Tug Hill Plateau has on winter storms and the love–hate relationship that Mother Nature has with snowpacks in the eastern U.S.

The graph shows the total snow depth at two sites.  The first is Sandy Creek (elevation 475 feet) at the foot of the Tug Hill Plateau.  The second is North Redfield (elevation 1275 feet) on the western slope of the Tug Hill Plateau.  These are the middle two sites in the image below.

These sites may be only 800 feet difference in elevation, but the contrast in storm intensity and snowpack is enormous and impressive even for a hardened mountain weather scientist and powder snob like myself.

Note first the dramatic increase in snow depth during nearly all winter storms, which I have identified with green or blue shading.  The green indicates periods where the increase in total snow depth and the new snowfall at North Redfield is substantially larger than at Sandy Creek.  This is largely a result of precipitation enhancement over the Tug Hill Plateau.  There is one curious exception to this and that is the storm that occurred on 12-15-2013 (indicated by blue shading) when the two sites received fairly similar snowfalls.  Understanding why some lake-effect storms bombard the lowlands as much as the uplands is one of the problems we hope to work on with the data we have collected in our field program.

Next we have the impressive snow depth of more than 1 meter (nearly 40 inches) achieved at North Redfield in December.  By eastern standards, that is an impressive snowpack, but we could have achieved much greater depths if Mother Nature wasn't so cruel.  She has beaten and battered the snowpack with three thaw and rain events.  These thaw and rain events are indicate by red shading and feature a much more rapid decline in total snow depth than produced by settlement of the new snow after storms.  Collectively the three thaw and rain events wipe out about 60 cm of snow depth (more if you include the graduate loss of snowpack during the first thaw event around 12-22-2013).  If we could only remove these thaw and rain events from the climate system!

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