This pair of maps shows average percent snow cover in December 2008 and February 2009, the first and last months of meteorological winter in the Northern Hemisphere.
Acquired July 22, 2011, and July 8, 2011, these false-color images compare conditions around Lonquimay, Chile, which was buried in several feet heavy snow.
Flying over the Sierras in a Twin Otter aircraft, NASA scientists are finding new ways to measure the amount of water stored in the winter snowpack with greater accuracy than ever before.