The worst flooding in over 20 years turned the Northern California community of Guerneville into an island on Wednesday after authorities ordered thousands of residents to get out or risk being stranded for days. Water rose to the roofs of homes and submerged cars as the rain-swollen Russian River overflowed its banks, forcing authorities in Sonoma County, about 70 miles (110 km) north of San Francisco, to evacuate 3,600 people, local authorities reported. “I’ve been here 30 years. I’ve never seen it rain so hard,” said Brian Gipson, director of marketing at the Farmhouse Inn hotel near Guerneville, which evacuated guests after water flooded its car park a third of a mile from the river. The nearby city of Santa Rosa got 4.64 inches (11.8 cm) of rain, smashing its previous record of 1.56 inches (4 cm) in a single storm, according to National Weather Service (NWS) data. “We have not reached the peak yet,” NWS meteorologist Carolina Walbrun said of the flooding. The Russian River had risen to over 43 feet (13 meters) by Wednesday afternoon, well over flood stage, and was set to crest at 46 feet (14 meters) by 9 p.m, its sixth-highest level on record, according to the weather service. The flooding was set to be the worst since 1995, when the Russian River rose to 48 feet (14.6 meters), and was caused by a so-called atmospheric river of moisture from the Pacific Ocean stalling over the county, Walbrun said. “Guerneville is land-locked,” the office of Sonoma County Sheriff Mark Essick said on Twitter. “You cannot get into or out of town. All roads leading to the community are flooded.” The evacuation orders affect about two dozen communities stretching dozens of miles along the river, including Guerneville, with a population of more than 4,500. “We hope everyone has evacuated, the roads are closing quickly,” Sonoma’s sheriff said on the department’s Facebook page, showing a video of brown, muddy water rising above a road and flooding homes. Residents got around flooded towns in kayaks. A California Highway Patrol helicopter landed on a dry section of street in Guerneville to evacuate a woman with a serious medical issue, the sheriff’s office reported. Boats and jetskis were deployed on the river to help with the evacuation, Essick said. The Russian River was not expected to fall below its flood stage of 32 feet (9.8 meters) until 12 a.m. (0300 ET) on Friday, Walbrun said.