California has been hit by a series of deadly storms in recent weeks with more forecast to come.
Communities living near the river are under an evacuation order, as authorities warn the cresting waterway could cut off homes and businesses from essential services.
Though some people have opted to stay behind, including real estate investor Johnny Reyes.
He has sandbagged his home in the community of Spreckels.
"The roads might get flooded, but as far as our house is concerned, our house is built pretty high. So I don't think it'll reach that level. But like I said, I don't know, it's mother nature's decision, so we have to wait."
Retiree Diane Souza has also opted to stay and ride out any potential flooding with her husband.
"We've sandbagged our garage. Our house is up off the ground so we really didn't need to do much of sandbagging of that, about four to five feet off the ground.// And my husband went and got some provisions, just things we needed, so if we're going to be here two to three days or however long we may be stranded, we're good to go."
A historic stretch of heavy rains and fierce winds since the end of December has caused widespread flooding, punishing residents from the Bay Area to Los Angeles.
Towns have been submerged, wind gusts have downed powerlines, and dozens of roadways have been made impassable by mudslides.
As many as 19 people have been killed in the storms,
including a woman who rescuers found drowned in her submerged car.
And it's not over yet.
The National Service says at least two more storm systems are set to pound the state over the weekend, including another so-called "atmospheric river", characterized by dense moisture funneled into California from the tropical Pacific.
The state has already been hit with seven such weather systems over the past two weeks.
