Flash flood warnings are in effect for the Pescadero Creek in San Mateo County and Big Sur River in Monterey County, a forecaster at the National Weather Service said.
A flash flood warning for San Lorenzo River in Santa Cruz County expired just before 6 p.m., forecaster Diana Henderson said.
The weather service issued the warning for the Big Sur River at about 5:30 p.m. It is expected to last until 7:15 p.m., Henderson said.
The warning for the Pescadero Creek was issued just after 5 p.m. and is expected to be in effect until about 6:30 p.m., she said.
Water levels have dropped along the San Lorenzo River, but hundreds living nearby have been evacuated, authorities said.
Water levels in the Pescadero Creek and Big Sur River are rising to just under flood stage, Henderson said. Forecasters expect water levels to start dropping early this evening.
Those living along the river and creek will be affected, Henderson said.
Others should stay away and pay attention to weather advisories, she said.
"Don't go swimming," Henderson said.