A fire that erupted Wednesday on the north side of Corona Municipal Airport burned about 35 acres before crews began making headway.
The non-injury blaze was reported shortly after 1 p.m. within the Prado Reservoir bordering Riverside and San Bernardino counties, according to the Corona Fire Department.
Nearly 200 personnel from Corona and the county were sent to the location and encountered flames in thick vegetation, burning at a moderate rate away from the airport. Five Cal Fire air tankers and two water-dropping helicopters made runs on the brusher until nightfall, slowing its progress.
Several structures were threatened, but crews prevented the flames from causing damage, according to reports from the scene.
By 5 p.m., the fire was 15% contained, according to the Corona Fire Department.
The blaze started in the same general area as a small fire that began in the predawn hours and was contained Wednesday morning. There was no word on whether the two are connected, or what might have sparked either blaze.
The airport was shut down because of the firefighting activity, and a temporary flight restriction was imposed, covering a five-mile diameter space around the field and up to 5,000 feet.
Crews were expected to remain on the fire lines through the night.