A slow-moving atmospheric river that soaked already saturated soil during the first half of the workweek has caused a large North Bay river to soar above flood stage and beyond, forcing scores of people to flee their homes and businesses in search of higher ground.
The rising Russian River at Guerneville, which has already crossed above the "major" flooding mark of 40 feet, is slated to crest at 46 feet late Wednesday evening, according to weather officials. That predicted crest level at Guerneville, a small Sonoma County community consisting of about 4,500 people, would be the highest the area has seen since 1995 and sixth highest on record.
"Guerneville is officially an island," the Sonoma County Sheriff's Office wrote on Facebook Wednesday morning. "Due to flooding all roads leading to the community are impassable. You will not be able to get into or out of town without a boat today."
Luis Lowenbery, an employee at Hotel R3 in Guerneville, told NBC Bay Area that the entire ground floor of the hotel was under water Wednesday afternoon. Lowenbery said he's stuck on the property but is able to stay dry on the second floor.
"Everything is under water, restaurant, all the rooms, the bar, everything, the offices," Lowenbery said. "Everybody was evacuated [Tuesday] afternoon because we knew it was going to come in but we weren't expecting [the water] to come in last night around 11."
Sonoma County officials have declared a local emergency due to the devastating flooding in parts of the county that has forced residents from their homes.
People in communities situated up and down the Russian River were ordered to evacuate Tuesday. Those who have fled their homes and businesses could be in a holding pattern until late Thursday evening when the river is expected to drop below flood stage.
Residents who can't evacuate are advised to shelter in place, said Rohish Lal, a Sonoma County spokesperson. About 55 people stayed at the evacuation center in Santa Rosa Tuesday night and 25 people arrived at the evacuation location in Sebastopol, Lal said.
In addition to the Russian River at Guerneville, at least two other spots in Sonoma County — the Russian River at Digger Bend near Healdsburg and Mark West Creek near Mirabel Heights — remain in "major" flooding territory as of Wednesday afternoon.
Across the North Bay in Napa County, the Napa River near Napa appeared to crest at 26.47 feet — about 1.5 feet below the "major" flooding classification — Wednesday morning, according to weather officials. That section of river is expected to drop below flood stage by Wednesday afternoon.
Rivers and streams across the waterlogged North Bay rose rapidly since the start of the week due to relentless downpours and runoff.
Since the storm arrived, the small community of Venado in Sonoma County picked up 21.56 inches of rainfall, according to the National Weather Service. Nearby Cazadero recorded 11.70 inches. Santa Rosa collected 7.84 inches.
While the heaviest rain has passed through the Bay Area, lingering showers will hang around through Wednesday, according to the weather service.