SAN FRANCISCO (CBS SF) -- Heavy rain across the Bay Area continued to cause headaches Monday evening as the first of two winter storm systems made for dangerously slick roads and increasingly windy conditions.
Early Monday evening, what appeared to be a large tree branch came down in San Francisco, narrowly missing a Muni bus.
The incident happened shortly before 6 p.m. and involved a 12 bus on Sansome Street near Pacific.
There was no word on injuries or whether the bus needed to be taken out of service.
The heavy rain continued to have an impact on freeways as the evening commute began.
Puddles on the upper deck of the Bay Bridge were leaking onto the lower deck below, giving cars on east bound 80 unexpected showers.
So much rain was falling, freeway storm drains backed up causing hydroplaning conditions such as on one ramp to eastbound Highway 24.
There was also flooding on city streets in Oakland.
One section of High Street flooded with about a foot of water leading to a back-up across some train tracks. Oakland police kept the tracks clear as cars waded through the water.
And several low-lying streets near the Oakland Coliseum were also partially submerged, making for hazardous driving conditions.
By early evening, 24-hour rain totals from the first of the two storm systems were impressive. Kentfield had received over three inches, while Ben Lomond in the Santa Cruz Mountains had gotten 2.8 inches.
San Francisco received over two inches, marking the first time the city had gotten more than two inches of rain in a calendar day since December 2014.
The storm front roared into the Bay Area early Monday, triggering dozens of accidents during the morning commute and flooding a section of northbound Highway 280 in San Francisco, authorities said.
The heavy rain was also raising the possibility of debris flows in the area of the North Bay wildfire with growing concerns over possible flooding and landslides.
A Flash Flood Watch has been issued for the North Bay mountains and valleys from noon Monday to late Monday night, National Weather Service officials said.
"Everything is soaking into the ground at this time, but if it gets very heavy, it could trigger a flash flood warning," National Weather Service meteorologist Steve Anderson said.
A Flash Flood Watch means that conditions may develop that cause flash flooding, which is very dangerous. North Bay residents were urged to be prepared to leave if a Flash Flood Warning is issued. A warning means flash flooding is occurring or imminent.
- KPIX 5 Weather Center: Current Conditions, Forecast, Maps
- Rainfall Totals - National Weather Service
Winds were strong and gusty by afternoon, with peak winds forecast between late afternoon through Monday night. Breezy conditions will remain through Tuesday.
Flooding was a problem for commuters on Monday morning. The California Highway Patrol reported its officers had responded to numerous accidents and the Highway 280 flooding had backed up traffic heading into San Francisco all the way to the Highway 1 junction.
The whole on-ramp from Sixth Street to Interstate Highway 280 was flooded, according to the CHP.
Six inches of water was reported on the off-ramp from northbound Interstate Highway 880 to 23rd Avenue in Oakland, CHP officials said. Eight inches of water was blocking the off-ramp from northbound Highway 880 to Broadway in Oakland.
A pickup truck rolled over on Highway 24 near College Avenue in Oakland, blocking three lanes of traffic for more than an hour.
Meanwhile, an SUV flipped over on Highway 17, slowing the commute to Silicon Valley through the Santa Cruz Mountains. Fortunately, no major injuries were reported.
Monday afternoon, a fatal crash on Page Mill Road near Palo Alto also caused major traffic delays.
At 12:25 p.m., Palo Alto police confirmed that a vehicle had struck a tree on Page Mill Road between Coyote Hill and Deer Creek roads, just outside Palo Alto city limits.
According to CHP spokesman Officer Art Montiel, the driver was heading east in the left lane when he lost control and struck a tree in the median.
The solo driver was unrestrained when, for reasons still being investigated, he drifted off the road and struck a tree. He suffered fatal injuries, Montiel said.
The man was pronounced dead at the scene. His name is not yet being released.
Palo Alto police stressed that everyone should drive with caution in the area as authorities investigate the crash and to expect delays while the scene is being assessed.
The crash is being investigated by the CHP.
The South Bay was also paying attention the rainfall levels, just under a year after catastrophic flooding in San Jose.
San Jose resident Felix Quintero stopped by one of the city's free sandbag stations to load up. His house has flooded twice before. Now every time it rains, he is on edge.
"I can't sleep sometimes because of that, you know? I have some kind of anxiety," said Quintero.
Along Rock Springs Drive -- one of the most heavily damaged areas in last February's floods -- residents said they keep an eye on Coyote Creek every time it rains.
But this year, the Anderson Reservoir – the source of Coyote Creek's water -- is being kept at a lower level to help avoid a repeat of that disastrous flood.
But some are trying to see the positive side, hoping this storm brings needed rain but not too much rain.
"As long as we don't get the flooding that we got last year," said San Jose resident Neil Anderson. "You want somewhere in the middle."
Residents in the North Bay are also facing challenges from the weather system, especially those who reside in the area affected by the Wine Country wildfires in Oactober.
Over the last few months, homeowners and city officials in Santa Rosa have been preparing for the winter rains.
The Fountaingrove neighborhood is one the city is particularly worried about. It is a very hilly area that was hit hard by the fires, a combination that leaves it particularly vulnerable to mudslides.
"Our house didn't burn and I'm very grateful, believe me, But we have our own set of problems to deal with," resident Michael Fiumara told KPIX 5.
Fiumara's home was one of only two houses on his street that survived the Tubbs fire. Flames came within a few feet of his back door.
"What I'm trying to do is watch out for additional slides," said Fiumara.
He said ever since the fires burned away the brush, the hillside behind his home has become unstable. Fiumara is worried the heavy rains could lead to a massive mudslide.
"I'm monitoring some of the areas that look like they could move," said Fiumara."So what we've done is we've taken stones and placed them in place, so it doesn't come down."
A wind advisory had also been issued for the Bay Area with gusts expected later Monday and overnight of 15-40 mph.
Southern Marin County received the brunt of the first system with Larkspur and Kentfield both reporting near an inch of rain by 8 a.m. San Francisco had over half an inch as had Dublin, Brentwood and Redwood City.
Forecasters said first storm was rolling into the Bay Area from near Hawaii while the second, more powerful storm, was expected to arrive Monday evening from the Gulf of Alaska.
The weather service also issued a winter weather advisory for portions of the Sierra Nevada above 7,000 feet (2,134 meters), forecasting about 4 to 7 inches of snow and up to 1 to 2 feet on higher peaks Tuesday.
It said travelers should prepare for difficult travel conditions, including gusty winds, low visibility and slick and snow-covered roads.
© Copyright 2018 CBS Broadcasting Inc. and Bay City News Service. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.
for more features.