Even as summer wanes, snowmelt and glacial runoff swell the rivers along Alaska’s southern coast. In this image, the Copper River (upper center) spills light grey sediments into the Gulf of Alaska. Upstream in Wrangell-St. Elias National Park, glaciers grind bedrock into powder as they slowly move along mountain valleys. This fine sediment is easily carried by water, even if it is slow moving. Where the river meets the ocean, the sediment gradually disperses, and the water fades from bright turquoise to dark blue.

This image was taken on August 22, 2003 by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite.

Image courtesy Jeff Schmaltz, MODIS Land Rapid Response Team at NASA GSFC

Instrument: 

Terra - MODIS