The recent push of the western trough east creating a favorable environment for frequent large scale snow systems along with widespread, early season cold has increased the snow cover significantly across the US. On December 1st, 20.2% of the US was covered with snow. By December 9th, that number increased by almost 47%! Only 2009's increase of 44.3% in the first 9 days of December has even come close.
Last year's snow cover map vs this year through December 9th: