Northern Californians living near parts of the Russian River were urged Tuesday night to evacuate as rain from an atmospheric river-fueled storm pushed the waterway to its flood stage of 34 feet, according to the National Weather Service.
Floodwaters were expected to rise throughout the night as the storm moved in, tapping tropical moisture from the Central Pacific and dumping rain throughout the region, including the Bay Area, the Sacramento area and wine country.
The area in the Sierra foothills devastated by last fall's Camp Fire in Butte County was not the biggest worry for forecasters, said National Weather Service meteorologist Johnnie Powell.
"We’re not really concerned about the burn area up there, because most of the rain is centered toward Lake County," which is southwest, he said.
However, flooding was feared in areas ravaged by the Mendocino Complex Fire, which was recorded as the largest wildfire in state history in August. Forecasters expected the Russian River and the Navarro River to crest in that area Tuesday night.
The Eel River in Humboldt County was also expected to reach flood state, according to the NWS. The Napa and Carmel rivers were under flood warnings as well.
An urban and small stream flood warning was issued for a wide swath of Northern California, from Redding to the north to Stockton to the south.
Some parts of Northern California could see 14 inches of rain by the time the system moves out Wednesday night, Powell said.
Santa Rosa, California, already set a one-day rainfall record with 5.66 inches, the National Weather Service stated Tuesday afternoon.
"We’re just getting an atmospheric river of rain coming in," Powell said. "The Bay Area, Napa County, Lake County, Sacramento northward -- that's where the main water hose is."
Snow was falling in the Sierra Nevada Mountains and other peaks above 4,000 feet, Powell said. An NWS forecast discussion called for "heavy to excessive lower elevation rains likely over Central to Northern California ... while very heavy snows accumulate through the Sierra."