In summary
Some Northern California cities have been soaked with almost twice their average rainfall, while southern cities are bone-dry. This season’s huge — possibly unprecedented — disparity works in favor of the state’s water supplies.
Welcome to CalMatters, the only nonprofit newsroom devoted solely to covering issues that affect all Californians. Sign up for WhatMatters to receive the latest news and commentary on the most important issues in the Golden State.
Lea esta historia en Español
A remarkably wet kickoff to Northern California’s rainy season has coincided with a desperately dry fall in Southern California — a huge disparity, perhaps unprecedented, between the haves and have-nots of rainfall.
Los Angeles usually gets several inches of rain by now, halfway into the rainy season, but it’s only recorded a fifth of an inch downtown since July, its second driest period in almost 150 years of record-keeping. The rest of Southern California is just as bone-dry.
At the same time, much of the northern third of the state has weathered nearly two months of storms, flooding and even tornadoes. Santa Rosa, north of San Francisco, has received more rain than nearly any other city in California — nearly two times its average rainfall to date. At the city’s airport, almost 7 inches fell on Nov. 20 alone, an all-time daily record.
Northern California is always wetter than the semi-arid southern half. But the scale of the north-south gap that has persisted for several months has stunned experts.
“There have been few if any years since 1895 … that have been so much above-normal in the northern part of the state while simultaneously so dry in the south,” Daniel Swain, a UCLA climate scientist, wrote in his blog Weather West. He added, in an email exchange with CalMatters, that “it is likely that the current north-south disparity is record-breaking in magnitude by at least some metrics.”
This season’s stark imbalance isn’t bad in terms of water supply. That’s because Northern California’s rain and snow feed major reservoirs, which provide much of the water used by Californians. If this occurred in reverse — a wet south and a dry north — most of the water would remain uncaptured, providing little benefit for supplies.