NOAA/ESRL/PSD Catalog http://esrl.noaa.gov/psd/thredds/catalog/Datasets/snowcover/catalog.html

Dataset Size Last Modified
     Folder  snowcover   --
         snowcover.mon.ltm.nc 781.3 Kbytes 2011-02-18T20:05:51Z
         snowcover.mon.mean.nc 19.25 Mbytes 2013-03-29T18:57:39Z

NOAA/ESRL/PSD at NOAA ESRL PSD see Info
THREDDS Data Server [Version 4.3.15 - 20121218.1126] Documentation