Cars drive through a flooded road in San Francisco on Dec 31, 2022.
Winter rain and snow typically provide much of the water used throughout the year in California, which has suffered several years of punishing drought. But when these storms, which are known as atmospheric rivers, are particularly severe or sweep through in rapid succession, they can do more harm than good, delivering too much water, too quickly, for the state’s reservoirs and emergency responders to handle.
One atmospheric river can be enough to flood homes, down power lines, and wash away hillsides and highways. But when several sweep ashore in a matter of days or weeks, as appears to be happening this week, the potential damage is multiplied. “It’s really helpful if the storms would be so kind as to space themselves out a week or two apart so we have time for water to move through the system,” said Jeanine Jones, an official with California’s Department of Water Resources.