Winter Westerly Winds Shifting North (image) University of Arizona Caption The late-winter/early-spring storm activity in the western US has shifted north since the late 1970s. This graphic shows how the peak winter storm tracks have shifted poleward since 1978. The blue line shows the storm track for February, March and April of 1978. The red line shows the track for the same months during the year 1997. Credit Stephanie McAfee, the University of Arizona, 2008. Usage Restrictions This image may be used only to accompany a story about the research described in this release. Credit must be given to: Stephanie McAfee, the University of Arizona, 2008. 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.