Timing of Runoff (image) Purdue University Caption The figure shows projected future changes in the timing of runoff in snow-dominated areas of the western United States. The timing of runoff shifts earlier in almost all areas as greenhouse gas concentrations increase. These snow-dominated areas currently act as natural reservoirs, with melting in the spring and summer providing critical fresh water throughout the western United States. A shift to earlier runoff could pose challenges for human consumption, agriculture, wildfire management and sensitive ecosystems. Credit Purdue University image/Diffenbaugh Laboratory Usage Restrictions None 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.