The MODIS Terra MOD10A2 Version 6.1 product provides a global Level-3 dataset representing the maximum snow cover extent observed over an eight-day period. The data are distributed in 10° à 10° tiles projected to a 500 m MODIS sinusoidal grid. Each tile is generated by compositing 500 m observations from the MODIS/Terra Snow Cover Daily L3 Global 500 m Grid dataset (MOD10A1). A bit-flag index is used to record the eight-day snow and no-snow chronology for each 500 m pixel, allowing users to track the temporal pattern of snow cover within the compositing period.