Hydroelectric power from dams like these account for roughly 20 percent of the state's electricity. Image courtesy of the U.S. Bureau of Reclamation.
Northern spring is a crucial time for such monitoring.
Scientists hope to figure out what the Pacific will do this year by running computer simulations. It's also much larger. The PDO has a positive phase and a negative phase. It matters little, however, since the short term climate effects are similar. The big debate among climate scientists is whether we are entering a long-lasting negative PDO episode.