Officials in the Monterey Bay area warned that more of the flooding that has devastated parts of California could temporarily turn the Monterey Peninsula into an island. Several communities in the area were ordered to evacuate Wednesday.

“Due to the rising flood waters along the Salinas River, there is a strong possibility areas on River Road, Spreckels, and the Peninsula will be cut off,” the Monterey County Sheriff’s Office posted on its Facebook page Thursday. “There is a possibility residents will not be able to leave or return from the peninsula area through Highway 1 and Highway 68 this weekend due to Salinas River flooding.”

Flooding is expected to begin Thursday at noon and last until Friday. In addition to Wednesday’s evacuation orders, tens of thousands more people along the river were under evacuation warnings.

While the threat of Monterey Peninsula turning into an island is new, the threat of additional flooding has been something that many in California have worried about for all of 2023 so far. Forecasters have predicted more torrential rain for Friday.

“It was terrifying. I don’t think I slept the whole night and the rain was… you just you can’t imagine. It’s like just living in the waterfall. This was really horrific,” Montecito resident Susanne Tobey said Wednesday. “I was just worried about our neighbors and the community at large.”

The death toll from the flooding climbed to 18 after a woman was found dead Wednesday. The discovery came a day after she call 911 to report her vehicle was stuck in floodwaters north of San Francisco.

“Marine Unit deputies and Sonoma County Fire Swift Water Rescue personnel… found a car submerged in flood waters approximately 100 yards off the road,” the Sonoma County Sheriff’s Office said on Facebook Wednesday. “The car was submerged in approximately 8-10 feet to water, making it difficult to determine if the car was occupied. A Marine Unit deputy dove into the water and determined the car was occupied but the occupant had died.”

NBC News and The Associated Press contributed to this report.