storm drain
© Gary Reyes/Bay Area News Group
The water level is close to running over the spillway at Lexington Reservoir in Los Gatos, Calif., on Tuesday, Jan. 10, 2017. Heavy rains have begun to fill area reservoirs.
The powerful storms that soaked Northern California over the past week did more than trigger power outages, mudslides and flash floods.

They sent roughly 350 billion gallons of water pouring into California's biggest reservoirs — boosting their storage to levels not seen in years, forcing dam operators to release water to reduce flood risks and all but ending the five-year drought across much of Northern California, even though it remains in the south, experts said Monday.

"California is a dry state and probably always will be in most years, but we certainly don't have a statewide drought right now," said Jay Lund, a professor of engineering and director of the Center for Watershed Sciences at UC Davis.

"We have to be careful about crying wolf here," he said. "You have to maintain credibility with the public when there are critically dry years, so you have to call it like it is when conditions improve."

On Monday much of the state began drying out from the weekend drenching that caused at least three fatalities and triggered flooding in Morgan Hill, Sonoma County, Yosemite and parts of the Sacramento Valley, even as forecasters said another storm system was coming in Tuesday.

That new storm system should bring 1 to 2 inches of rain around much of the Bay Area, and up to 6 inches in the Santa Cruz Mountains and Big Sur, with more rain in the North Bay, tapering off Wednesday.

"It's not going to be as heavy," National Weather Service forecaster Steve Anderson said. "But even though the amount of rainfall will be less, the impact will still be there."

Despite concerns that the weekend storm's warmer temperatures would significantly deplete the Sierra Nevada snowpack, it grew significantly. Last Monday, it was 70 percent of historic average. This Monday, it had grown to a staggering 126 percent for this time of the year.

In fact, since Oct. 1, more precipitation has fallen across the key watersheds of Northern California — eight areas from Lake Tahoe to Mount Shasta that feed many of the state's largest reservoirs — so far this winter than any time since 1922, according to state totals.

In a typical year, that "Northern Sierra eight-station index" receives 50 inches of precipitation. As of Monday it was already at 40 inches — 199 percent of the historic average for this date — and running slightly above 1982-83 and 1997-98, both of which were marked by severe El Niño flooding.

The rain and snow could shut off, as happened three years ago in January, although the reservoirs now are so full in many areas there wouldn't be water shortages for several years.

Officially, California's drought won't end until Gov. Jerry Brown rescinds or revises the emergency drought declaration he signed in January 2014.

reservoir levels
Lund, of UC Davis, said that because other parts of the state — particularly Santa Barbara and other parts of Southern California — are still well short of rain and suffering from low reservoir levels, Brown should issue an updated drought declaration that reflects the regional differences.

That is one of the options he is considering, said Nancy Vogel, a spokeswoman for the state Natural Resources Agency. But a decision may not be made until the end of the winter snow and rain season, she said.

"It's early and the precipitation patterns could dry up at any time," she said. "We'll see where we are in March or April."

Rain from Sunday's storm fell in sheets at time, flooded roads and storm drains, and toppled trees. It fell most forcefully in the Big Sur area of Monterey County, dumping more than 12 1/2 inches over a 72-hour period. More than 9 3/4 inches fell in the Lexington Hills in Santa Clara County and more than 6 inches soaked areas of San Mateo County.

In Contra Costa County, 4 1/2 inches of rain fell atop Mount Diablo, and 3 1/4 inches fell in Orinda. San Francisco and parts of Oakland saw 2 1/2 inches of rain. Only 1.03 inches fell at Mineta San Jose International Airport, but that still set a record for Jan. 8.

More importantly, the recent storms have sent reservoirs swelling.

The 154 largest reservoirs tracked by the state Department of Water Resources added 1.1 million acre feet of water from Jan. 1 to Monday, boosting their capacity to 97 percent of historic average, said Maury Roos, longtime state hydrologist.

"It's excellent news," said Roos. "I don't make the decision on the official drought, but from the Bay Area north we are in good shape for this time of the season."

Specifically, Loch Lomond, the main reservoir serving Santa Cruz, filled to capacity. All seven reservoirs that serve the Marin Municipal Water District were 100 percent full. Pardee Reservoir, the main reservoir that provides water to 1.3 million people in Alameda and Contra Costa County, spilled on Monday.

Lexington Reservoir, near Los Gatos, has gone up 31 feet since New Year's Day, surging to 93 percent full from 42 percent full a week ago.

Perhaps most dramatic was San Luis Reservoir, California's fifth largest, located between Gilroy and Los Banos. Sitting at 10 percent full in August, it now is 66 percent full, having risen 134 feet. At current rates, it may fill to the top for the first time since 2011, said Roger George of Fresno, a professional guide who leads fishing trips for striped bass there.

"Back in August, it was scary. I was beginning to wonder if we were going to have a die-off of the fish," he said. "Now it looks like an ocean."

Similarly, the state's second-largest reservoir, Oroville in Butte County, has risen 35 feet since New Year's Day. It added 250,000 acre-feet of water over the weekend, enough for 1.3 million people's needs for a year. It now stands at 64 percent full, or 102 percent of historic average.

On Monday, officials at Yosemite National Park announced they would reopen Yosemite Valley Tuesday morning. The park suffered some damage when the Merced River jumped its banks, but the flood levels were only two or three feet above flood stage, less than had been earlier feared.

The storm unleashed mud and rock slides throughout the Santa Cruz Mountains early Monday, halting traffic during the morning commute on Highway 17. A slide just north of Scotts Valley shut down northbound lanes and traffic was detoured onto the southbound side.

In Gilroy, two people were rescued Sunday night from the second story of their home after water surrounding the residence rose to about four feet. The San Jose Fire Department's Urban Search and Rescue team had to use a boat to help the people out of the home, according to Cal Fire spokeswoman Pam Temmermand.

At least three people were killed in the weekend storm, including 57-year-old Jarnail Singh, whom police said lost control of a white cab he was driving and crashed into an estuary near the Oakland International Airport on Sunday morning.

An unidentified motorist also died in a crash on Interstate 880 in Fremont.

A San Ramon woman died Saturday after a tree fell on her at a golf course in San Ramon. Deborah McKeown, 56, was taking a walk when high winds knocked over a tree that landed on her. McKeown, a freelance writer for the Bay Area News Group who wrote under the pseudonym Kathleen Ford, was taken to a hospital from the Canyon Lakes Golf Course on Bollinger Canyon Way.