A weak winter storm system dropped thin bands of snow across areas of Oklahoma and Kansas on January 12, 2013. Three days later, the Earth-Observing 1 satellite acquired this view of the snow.
Scientist Tom Painter examines the differences between pure and dirty snow. A rise in dust can be a critical influence on snow-fed water supplies in the American West.
Snow covers the ground in a solid swath from eastern Arizona to the edge of a massive winter storm in Indiana and Michigan in these images from February 2, 2011.