June 2016:

Data for dates 2009150 to 2009186 have been reprocessed. Apparently there was an error incorporating 
AVHRR data in the maps which for some reason went unnoticed. 

AVHRR files for N.Hemisphere for these days were recovered from the archive and global maps were reprocessed
There were no AVHRR data in the archive for the S.Hemisphere, therefore on some dates within 2009150-2009186
S.Hemisphere snow cover was not updated.

Time series of snow extent at ftp://ftp.star.nesdis.noaa.gov/pub/smcd/emb/snow/snow_extent_plots/data/
have been updated accordingly.