River Ice Cover (IMAGE) University of North Carolina at Chapel Hill Caption Ice cover on the Yukon River approaching its confluence with the Tanana River in Alaska. Credit Courtesy Landsat imagery/NASA Goddard Space Flight Center and U.S. Geological Survey Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.