The rapid reversal of the dry conditions in the pacific northwest has fueled a surge in Columbia River flows and snowpack. Bonneville Power Administration data shows that hydro generation has exceeded 2013 levels by over 5GW in the last three weeks. This excess has translated into more power headed south to California and less thermal (coal and gas) generation within the BPA system.
Here are the 7 day trailing averages in Hydro, Exports, and Thermal Generation. The historical patterns indicate that the gains won't persist at these levels through summer.