SAN FRANCISCO (CBS/AP) — Heavy rains and wind were walloping the Bay Area, flooding roadways, closing roads and causing airline flights to be canceled Friday afternoon, according to city, airport and utility spokespeople.

As of 2:35 p.m., the Rohnert Park Expressway in Rohnert Park in the North Bay was closed between the Rancho Verde Mobile Home Park and Stony Point Road due to flooding, city officials said. Motorists were advised to avoid the area, according to the Rohnert Park Department of Public Safety.

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The National Weather Service issued several flood warnings and advisories throughout Northern California ahead of Friday’s expected atmospheric river, stretching to the Truckee River near Lake Tahoe.

A flood advisory was issued for parts of south central Sonoma County due to minor creek and road flooding. The advisory was initially set to expire at 2 p.m. The advisory was later expanded and extended until 10 p.m.

Emergency crews in the East Bay responded to an accident in the Oakland Hills near Grizzly Peak Boulevard after a car plunged 100 feet down an embankment Friday morning shortly before 9 a.m.

Authorities did not know how many people were in the vehicle at the time of the accident and initially found no victims inside once the vehicle was located. A body was found near the crash scene Friday afternoon, Oakland fire officials later confirmed.

An injury accident shortly after 1 p.m. in Castro Valley triggered a severe traffic alert on eastbound I-580 west of Redwood Road. CHP said a jack-knifed big rig collision was blocking the left lanes. The accident was cleared and all lanes reopened by about 2:20 p.m.

In Sonoma County, flooding shut down CA-1 at Fallon Road in both directions at around 1:30 p.m., according to CHP. Officials were able to reopen the roadway at about 2:40 p.m.

At around 1 p.m., CHP in Marin County announced that Highway 1 was closed at Bay Road in Tomales due to flooding.

Earlier Friday, fender-benders and more serious accidents triggered by slick roadways made for a difficult morning commute. A truck spun out on eastbound Highway 4 at Port Chicago early Friday morning, closing three lanes of traffic and snarling the busy East Bay freeway.

A crash on the approach to the Bay Bridge toll plaza at around 6:30 a.m. also slowed eastbound traffic into San Francisco.

The Santa Cruz Mountains were seeing some of the heaviest rain, with the intense precipitation on Highway 17 making for a treacherous ride. Several accidents were reported on the highway Friday, including an injury accident that sent a car 100 feet down an embankment shortly before 2 p.m. that closed a northbound lane of Highway 17 near Summit Road.

A subsequent crash in the same area on southbound Highway 17 also closed the shoulder and right lane of the highway, further constricting traffic.

San Francisco officials have set up temporary flood barriers in the Mission District. The low-lying area around 17th and Folsom has been called the most flood-prone spot in the city.

For this storm, in addition to installing flood barriers, monitors will be present 24-7.

Early rain totals for the storm found precipitation concentrated in the North Bay as expected. As of about 5 p.m., Venado in Sonoma County had received 4.84 inches of rain, while Mill Valley got 2.72 inches.

San Francisco received 1.28 inches of rain, while Concord received .79 inches. The peak of Mount Diablo received considerably more, measuring 2.38 inches of rain.

The storm was also impacting air travel. At SFO, airlines were proactively cancelling flights to reduce the length of delays on their remaining flights.

According to SFO officials, cancellations totaled 147 — over 10 percent of the total flights scheduled at SFO for Friday — as of around 2:30 p.m., mostly on short-haul flights along the West Coast. A Traffic Management Program was in effect for inbound traffic, delaying some inbound flights up to four hours, SFO officials said at around 4:45 p.m.

While there is no ground stop, the FAA does have a ground delay program in place for SFO Friday. Delays are averaging 30-45 minutes as of late Friday afternoon.

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There were no significant weather delays beyond around 15 minutes for Oakland International Airport and Mineta San Jose International Airport.

There were also concerns on the affect several inches of rain would have on burn-scarred areas of wine country and the test in could present for the partially repaired spillway at the nation’s tallest dam.

In Sonoma County, which was devastated by wildfires in October, the weather service predicted 4 to 6 inches (10-15 centimeters) of rainfall through Sunday. Even if the rain doesn’t pan out, “it’s better to be prepared than not,” said county Supervisor David Rabbitt.

KPIX 5 spoke with Santa Rosa fire officials who said they think the work they’ve done should be enough to prevent any big landslide type problems tonight.

In fact, they might be more worried about the small-scale runoff from some of the lots.

“So that’s why you’ll see a lot of these gravel bags and grass swaddles around the hillside communities,” said Santa Rosa Assistant Fire Marshal Paul Lowenthal. “They are there to protect our waterways. They are there to keep the runoff and the silt and dirt out, from impacting our creeks and our storm drain systems and creating any issues downstream.”

Emergency officials said serious problems such as land just giving way and sliding generally happens when rain starts falling at the rate of one half inch per hour.

They currently do not expect that rate of rainfall, but things could change.

Workers have been monitoring hundreds of storm drain inlets, especially the ones protecting the neighborhoods destroyed by the fires, said Lowenthal.

Some areas of the Santa Cruz mountains could see up to 8 inches (20 centimeters) over a three-day period, prompting forecasters to warn of possible flooding, mud and rock slides.

Yosemite National Park officials canceled camping reservations for this weekend because the warm Pacific storm is expected to have a significant effect on the park and surrounding areas starting Friday. Roadways, campgrounds and other facilities could be affected.

The National Weather Service issued a flood watch for the Yosemite area from 11 p.m. Friday through 11 a.m. Sunday.

To the north, California Department of Water Resources officials warned this week that they may have to use the partially rebuilt spillway at Oroville Dam for the first time since repairs began on the badly damaged structure last summer.

Lake Oroville has been slowly filling up all winter but as of Thursday morning, more water was being released through smaller outlets than was flowing in. The water level was at 793 feet (242 meters) and dropping. Water managers say they’ll open the gates to the main, partially repaired spillway if the lake level reaches about 830 feet (253 meters).

In February 2017, a massive crater opened up in the main spillway, a 3,000-foot concrete chute that releases water from Lake Oroville, which is California’s second-largest reservoir. Crews shut down the spillway for inspections just as a major storm dumped a torrent of rain in the Feather River basin. With water releases stopped, the lake quickly filled to capacity and water began flowing over a concrete weir that serves as an emergency spillway. It had never been used.

The water eroded the barren hillside beneath the concrete, leading to fears the weir would collapse and release a 40-foot (12-meter) wall of water that would swamp communities and destroy levies for miles downstream. Authorities ordered nearly 200,000 people downstream to flee.

California officials say they hope to avoid using the main spillway but are confident it can safely function if needed.

“It’s a big storm, it’s a warm storm,” said Erin Mellon, a spokeswoman for the Department of Water Resources. “Obviously we have plenty of flood capacity within the lake considering it’s still 110 feet (34 meters) below the top of the reservoir.”

Construction crews last year fully rebuilt about a third of the spillway with rebar-reinforced structural concrete that’s anchored into bedrock. The other two thirds were left with temporary concrete until construction resumes.


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