Lots of issues divide Southern and Northern California: The Dodgers vs. the Giants. Hollywood vs. Silicon Valley. Southern Californians say “the” before naming a freeway; northerners don’t.
Now, after this past weekend’s soaking storms, there’s a new difference emerging: the drought.
As the state faces a possible fourth year of drought, Northern California is enjoying a healthy wet winter so far, with rainfall levels at 100 percent of their historic average or above in nearly every city, and reservoirs, while still not back to normal, steadily filling. But rainfall totals in the south are anemic, and falling further behind as each major storm only drenches the northern part of the state, leaving the south dry.
If the trend continues, this summer there may be two droughts in California: a mild one in the north that most residents barely notice, and a far more severe one in the more populated southern half of the state with more fire risk, smog, desperate groundwater pumping and more strict water rationing.
“We definitely want to see more rain down here. We are getting behind,” said Eric Boldt, a meteorologist with the National Weather Service in Los Angeles.
How big is the rain gap?
Up to 12 inches of rain fell in some remote Northern California areas over the weekend, with most Bay Area and Northern California cities receiving 1 to 3 inches from Friday to Monday.
But over the same time, Los Angeles received just 0.02 of an inch, and Riverside and San Diego got none.
In an average year, many Bay Area cities and LA basin cities receive about the same amount of rain. San Jose averages 14.9 inches in a normal year, the same as Los Angeles.
This year, however, since Oct. 1, San Jose has received 11.58 inches — 134 percent of normal for early February — while LA has received only half as much, 5.72 inches — good for just 70 percent of normal.
Although there are a few exceptions, most areas south of Fresno are similarly dry. Irvine is at 61 percent of normal rainfall while San Francisco is at 109 percent. Riverside is at 60 percent, while Oakland is at 107 percent. Palm Springs is at 36 percent, while Sacramento is at 120 percent.
“There is a big difference,” said Jay Lund, a professor of civil and environmental engineering at UC Davis. “Some people in Southern California may be feeling this year like nature doesn’t like Southern California.”
The reason is largely meteorological luck, say experts.
Two of the biggest storms that have hammered Northern California were both “atmospheric rivers.” Those are the so-called “Pineapple Express” storms that race in from the tropics. Although they provide up to half of California’s rainfall every year, they also tend to be narrow, only a few hundred miles wide.
As a result, the places that are in the bull’s eye where the “express” comes ashore get absolutely deluged. Places a few hundred miles away get nothing.
“With this system we had an atmospheric river coming from Hawaii,” said Holly Osborne, a meteorologist with the National Weather Service in Sacramento.
“Basically the moisture plume hit around the Oregon-California border, so if you were in the southern part of the state, you didn’t see much at all.”
Added to that, the Pacific Ocean remains unusually warm, which led scientists last year to raise the probability for El Niño conditions. But those conditions, which historically have meant higher chances of a wet winter for Southern California than Northern California, have failed to materialize because the ocean conditions haven’t triggered atmospheric changes needed for an El Niño.
“We never really got it,” said Boldt. “Now it’s February. It’s late.”
Southern California receives its water from many places, including the Colorado River, local reservoirs and groundwater wells. But a significant portion comes from the north, through the Sacramento-San Joaquin River Delta, and dry conditions will increase political pressure for more pumping.
To be sure, California has two more months in the traditional winter rain season. Trends could flip and several warm tropical storms could barrel into Southern California, evening the score. But for now, residents of the Southland are getting nervous.
“You can’t escape it. Everybody is talking about it,” said Sally Melcher, assistant manager of Sunset Nursery in Los Angeles.
“My roommate was just in Concord last week. She got drenched walking two blocks from a restaurant to the parking lot. We only got a tiny bit of rain here, just enough to get the plants damp.”
She laughed.
“It’s not fair!” Melcher added. “But I guess we should say it’s good that it’s raining somewhere.”
Paul Rogers covers resources and environmental issues. Contact him at 408-920-5045. Follow him at Twitter.com/PaulRogersSJMN
