(CNN) -- A raging wildfire north of Bend, Oregon, nearly doubled in size Wednesday, consuming 4,200 acres.
About half of the blaze, known as the Rooster Rock Fire, is in Deschutes National Forest-administered lands, and the remaining fire burns on private lands protected by the Oregon Department of Forestry. The fire was about 20 percent contained at 9 a.m. PT Wednesday, fire authorities said.
Fire officials asked residents of about 30 homes to evacuate Monday, and 70 homes were on standby, said
Lisa Clark, spokeswoman for the Central Oregon Interagency Dispatch Center.
A temporary flight restriction to 8,000 feet was in place for 5 miles around the fire as crews utilized helicopters and air tankers to fight the flames, the forestry department said. But fire officials said smoke and limited visibility hampered air support Tuesday. More than 550 firefighters are fighting the blaze.
The fire started around midday Monday in the Deschutes National Forest. The forestry department said the blaze grew quickly, stoked by 8 to 12 mph winds pushing it through a mix of sagebrush and ponderosa pine into both public and private forests.
The cause of the fire is under investigation.