Some low-lying areas of Marin County experienced tidal flooding on Monday, as coastal parts of the Bay Area are under a flood advisory.
Around noon, the Shoreline Highway near the Highway 101 interchange in Marin City was flooded. Video from chopper also showed someone kayaking on a flooded roadway due to the high-water levels.
In Mill Valley, a driver became stranded in the water before being towed to safety. The Mill Valley Police Department urged drivers to avoid Miller Avenue and Almonte Boulevard due to flooding.
The flooding comes as the National Weather Service issued a coastal flood advisory for low-lying areas near shorelines and tidal waterways until 3 p.m. Thursday.
"Rising tides will bring water and waves farther up the beach than normal, restricting escape from beaches and coastal areas. More substantial impacts are expected along bayshore Marin County where increased flooding is anticipated across low lying areas," forecasters said in a statement.
At the San Francisco tidal gauge, high tide at 12:15 p.m. Tuesday is expected to be 2.1 feet above normal. Wednesday's high tide at 12:56 p.m. is expected to be 1.9 feet above normal, while high tide at 1:43 p.m. Thursday is expected to be 1.7 feet above normal.
Forecasters said high tide will vary up to 90 minutes earlier or later along the coast and through San Francisco Bay, respectively.
The flood advisory remains in effect through 3 p.m. Thursday.
The exceptionally high tides on Monday also flooded streets, a popular bike path, as well as an off-ramp from Highway 101 near the Sausalito waterfront. For Chantz Rivera, a 29-year-old nearing the end of a cross-country walk from New York to San Francisco, the flooding became an unexpected obstacle.
"I'm seeing it slowly coming on the bike path but I didn't think it was going to be like this," Rivera said. "It was low in the beginning but it got crazy."
Rivera said he was unaware of the flood warnings and continued walking as the water rose around him.
"I was hoping it wasn't getting deep up to my neck," he said.
Other people traveling through the area found themselves stranded, unable to safely cross the flooded streets and pathways. Mandana Sigaroudi of Tiburon said the water was too deep for her to continue riding her tricycle.
"It's impossible because it will be way above my tricycle," Sigaroudi said. "Not possible to go back. I'm stuck for maybe two hours."
By later in the day, the tide had receded significantly, allowing conditions to return closer to normal. But scientists say the flooding could be an early warning of more significant coastal impacts this winter.
Gary Griggs, a geologist at UC Santa Cruz, said the elevated water levels are linked to El Niño conditions and ocean disturbances known as Kelvin waves.
These waves can move large amounts of warm water. The resulting changes in ocean circulation can contribute to higher sea levels along the California coast, increasing the risk of flooding during unusually high tides.
Griggs warned that the combination of elevated sea levels, upcoming king tides and winter storms could produce more serious flooding.
"The storms from El Niño, because of this warmer water and wind, haven't hit yet," Griggs said. "So it's not going to get better anytime soon."
For Gavin Smith, who lives on a houseboat nearby, Monday's flooding served as a reminder to complete overdue repairs before winter.
"I think this is a sign of things to come," Smith said.
He said leaks in his houseboat have gone unrepaired because of the difficulty of the work.
"I have some leaks. I've been putting it off because it's a hard job but I have to get up there and do it before December," Smith said.
Marin County is in the planning stages of a multimillion-dollar project to raise and widen portions of the bike path, with the goal of reducing future flooding and protecting the route against rising sea levels.
For Rivera, the flooding was another challenge on his long journey to San Francisco, but not enough to stop him.
"I was like damn all my stuff is going to get wet," Rivera said. "But I had no choice. I had to keep walking. I can't turn around now."
