By Diane Rommel One of the great charms of the holidays this year — at least for everyone whose GPS hadn’t routed them along summer-only dirt roads through the mountains — was the gleeful snow reports from the Sierra. Over two feet of snow fell on Christmas Eve alone; December 2021 would enter the record books as the third-snowiest month at the UC Berkeley Central Sierra Snow Lab, high up on Donner Pass, where snowfall measurements have been taken since 1879. Currently manning the record books (and the hugely relevant Twitter) was Dr. Andrew Schwartz (@snow_d0c), an atmospheric scientist speci…