California's ten year drought may end with extensive flooding. Following this week's winter storm, which coated the Sierra Nevada with up to 80 inches of snow, another Pacific storm is approaching from the west, directing a plume of Pacific moisture toward Northern and Central California.
Accompanied by a warm air mass, the system is forecast to drop a foot of rain across higher terrain; falling on the heavy snow pack, the rains may unleash flash flooding in the western canyons of the Sierra and trigger mudslides in the foothills. Of course, the highest peaks will receive more snow, increasing the risk of avalanches. In concert, a cold front is expected to dip southward from the Pacific Northwest, enhancing precipitation across most of the State.
Unfortunately, prolonged droughts often end with dramatic shifts in weather patterns and the parched landscape cannot absorb the copious precipitation. Excessive runoff thus leads to stream flooding, sometimes threatening dams and levees. While the deep Sierra snowpack is a welcome development, the heavy rains will likely be more damaging than beneficial. What California needs is a series of wet winters and springs, not a fire hose of moisture from the Pacific.