Daniel Hogan at the East River watershed (IMAGE) University of Washington Caption The Colorado River and its tributaries (including the East River watershed, shown here) provide water for hydropower, irrigation and drinking water in seven U.S. states and Mexico. But since 2000, water managers have struggled to predict how much water will come from the snowpack. The problem lies with the lack of rainfall in the spring, according to new research from the University of Washington. At first, the researchers wondered if the snowpack was decreasing because the snow was simply turning into water vapor — a process called sublimation. Shown here is Daniel Hogan at the East River watershed setting up a "snow pillow," which measures the weight of snowpack over the winter. Data from this equipment helped the team measure how much of the snow was sublimating. Credit Mark Stone/University of Washington Usage Restrictions For use with appropriate credit License Original 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.