The Cooling Snowpack

Courtesy of IARC

Here's a plot of temperatures at the Smith Lake met station near UAF West Ridge the past couple of  days. What caught my eye here was the one meter temperature yesterday during the afternoon (inside the magenta box). Notice that at one meter the temperature spiked around noon, but then fell back to right around freezing even as the 2, 4 and 8 meter high sensors remained in the upper 30s and lower 40s. Presently the one meter sensor is less than half a meter above the surface of the snowpack, and it looks as though on Friday the air just above the snow surface was isolated and kept cool in part by sublimation. This is much less evident on Saturday, when there was evidently better mixing, and the different between the 1 meter temperature and higher levels was mostly only a couple degrees.