Officials advised Oceanside residents near the San Luis Rey River to shelter in place as crews battled a 100-acre brush fire.
The City of Oceanside was moving at a moderate rate of spread as of 8:30 a.m., city officials said.
The fire was confined to the riverbed and firefighters were on scene working to contain the damage.
Flames sparked in the riverbed just east of College Boulevard at 1:30 p.m. Wednesday.
Dry brush and heavy vegetation pushed the flames to the north and south sides of the river, growing to 100 acres.
Oceanside officers went door to door and used a PA system to ask residents inside 100 homes to voluntarily evacuate along Andrew Jackson Street, Stallion Drive, Tyler Road and Leon Street.
All those evaucations have since been lifted.
The Oceanside Unified School District closed schools Thursday.