Terra MODIS true color image of the Western United States, 29 March 2004.
Drawing the border between the western valleys and the central plains of the United States, the Rocky Mountains traverse this true-color Terra MODIS image from March 29, 2004. Snow still caps the upper reaches of the mountains, though the spring season's warmer temperatures are fast approaching. Also visible is the bicolored Great Salt Lake in northeastern Utah. The lake's two colors are caused by restricted water circulation; a railroad crosses the lake on a rock-filled causeway, which restricts water flow between the two portions of the lake. Consequently, circulation is decreased, and the salinity level of the upper portion of the lake has increased. Salinity levels in turn affect the kinds of organisms that grow in the water, which in turn affect the color of the water when seen from space.
Tiny red dots scattered throughout the image mark locations where the instrument detected fires; the fires are concentrated in Montana (upper center), though a few were also detected in Idaho, Wisconsin, Nevada, Utah, and Colorado. Portions of California, Arizona, New Mexico, Kansas, and Nebraska are also visible.
Text and image courtesy of NASA's MODIS Land Rapid Response Team.