Month’s rains swamp most years’ January figures

What has felt like an especially wet January in California isn’t an effect of people becoming accustomed to the past half decade of drought.

It really has been an exceptionally soaking month.

San Francisco is experiencing the seventh-wettest January on record to date, according to the National Weather Service, and it’s nipping at the heels of January 1982, when a historic El Niño caused major flooding in California.

“The storms have been one after the other,” said Anna Schneider, a meteorologist with the weather service’s Monterey office. “We’ve gotten lot of rainfall. Most of our sites are at over 100 percent of normal.”

Graeme Paterson walks along the Embarcadero during a rainstorm in San Francisco on Sunday, Jan. 8, 2017. Graeme Paterson walks along the Embarcadero during a rainstorm in San Francisco on Sunday, Jan. 8, 2017. Photo: Gabrielle Lurie, The Chronicle Buy photo Photo: Gabrielle Lurie, The Chronicle Image 1 of / 9 Caption Close Month’s rains swamp most years’ January figures 1 / 9 Back to Gallery

The last week of intense weather has brought 8.77 inches of rain to San Francisco for this point in January. During the same period in 1982, 8.85 inches of rain had come down in the city, forecasters said.

At the height of the drought two years ago, San Francisco recorded no measurable precipitation for all of January.

Any chance of a record-breaking month, though, is effectively impossible. The rainiest January on record was in 1862, when 24.36 inches fell. What’s more, the latest round of rain will be the last significant precipitation for the month, forecasters said.

The wet month has been vital in digging California out of drought, and as of Thursday, more than 43 percent of the state is drought-free, according to the federal government’s Drought Monitor.

The month’s rain totals have been helped along by the latest streak of water-packed storms that drenched the Bay Area before thunderstorms moved in Sunday evening.

Residents in hard-hit areas were left scrambling as rivers surged, roadways flooded and earth gave way in mudslides that closed several roads and prompted flood warnings around the region.

Niles Canyon Road in the hills above Fremont, which was shut down because of slides, became the site of a search-and-rescue effort that had to be aborted because of weather. An 18-year-old motorist from Tracy crashed Saturday into Alameda Creek, where high waters prevented authorities from looking for the submerged vehicle over the weekend.

The areas left scorched over the summer by the Soberanes Fire in Monterey County and the Loma Fire in the Santa Cruz Mountains were under flash flood warnings for much of the day Sunday.

The weather service called the conditions in the Santa Cruz Mountains “life-threatening,” as debris flows posed extreme dangers to drivers.

“We’ve been really busy,” said Deputy Chief Jake Hess, with the California Department of Forestry and Fire Protection’s San Mateo-Santa Cruz division. “Santa Cruz County is a plate of spaghetti of small arterial roads. Those roads can became closed off, and a lot of these little communities have one way in and one way out.”

The San Lorenzo River surged over its banks Sunday, flooding residents in the Santa Cruz County communities of Paradise Park and Felton Grove. South of Los Gatos, mud and trees spilled onto Highway 17, closing lanes for part of the day.

In the North Bay, the California Highway Patrol closed Highway 37 in both directions between Highway 101 and Atherton Avenue in Novato due to heavy flooding. The stretch could remain closed for much of the week, authorities said.

Out on the coast, winds whipped up to 60 mph, prompting the weather service to issue a gale warning and an advisory for mariners to seek safe harbor.

Breakers close to 30 feet slammed the shoreline, making for sneaker waves and strong rip currents. The weather service issued a high surf advisory that will last until Tuesday morning.

Damaging conditions are expected to continue into Monday, with some rivers expected to flood as showers linger.

In Guerneville, flood-weary residents were again bracing for the Russian River to spill over its banks. The river was forecast to crest over its flood stage of 32 feet Monday morning.

Some parts of the state are approaching rainfall totals 200 percent of normal for the rain season that began on Oct. 1, said Jan Null, a meteorologist with Golden Gate Weather Services. However, much of the rain can’t be stored — many of California’s reservoirs are already filling up and releasing water.

The storms, though, are good news for the Sierra snowpack, which accounts for about 30 percent of the state’s overall water supply.

The storm was dumping an estimated 4 feet of snow in the Tahoe basin and up to 6 feet above 7,000 feet. The heavy dump prompted Caltrans to close Interstate 80 near the Nevada state line.

Travelers were told to stay home, and residents in the mountains were cautioned to brace for more road closures, blackouts and falling trees.

Several Tahoe ski resorts were affected by the snowstorm. Alpine Meadows was completely closed Sunday, and residents in the valley east of the resort were under a voluntary evacuation order. Placer County Emergency Services closed several roads in the area due to high avalanche danger.

Avalanches could impact other roadways around the Sierra as intense winds blast the mountains. The weather service recorded a wind gust of an astonishing 154 mph on a peak above Squaw Valley on Sunday.

The wet weather system was also causing havoc in still-drought-ravaged Southern California, where some areas were seeing the most significant storm in years.

Residents near the burn area left by the 41,000-acre Sand Fire in Santa Clarita (Los Angeles County) were ordered to evacuate over the weekend due to possible debris flows.

The early week stormy conditions were expected to calm to light showers Monday, then dry out for the rest of this wet January.

Chronicle staff writer Kurtis Alexander contributed to this report.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky