Firefighters were battling a brush fire Monday in Yolo County that burned more than 6,400 acres and was heading toward steep terrain.
The Monticello fire was 35% contained after igniting on Friday along the southeast shore of Lake Berryessa near the Monticello Dam and Highway 128, burning grassy oak woodland and heavy brush, according to the California Department of Forestry and Fire Protection.
Erratic wind shifts led to extreme fire behavior during the first few days of the fire fight, prompting evacuation orders for 40 homes.
Although evacuation orders were lifted Sunday and the blaze appeared to be burning away from homes, fire officials expected more challenges Monday, said CalFire spokesman Daniel Berlant.
As the fire burned north into rugged, steep terrain, access to the area was limited, he said.
Crews planned to use bulldozers to establish a fire line and aircraft to attack the blaze.
With temperatures expected to hit 100 in the region, the scorching heat poses a threat to firefighters, Berlant said. Three firefighters have suffered minor injuries, including heat exhaustion, he said.
The fire is about 18 miles from the Butts fire, which has burned for seven days in northern Napa County.
The Butts fire is 90% contained after starting July 1 off Butts Canyon Road in Pope Valley, charring 4,300 acres, destroying two homes and seven outbuildings.
Although all evacuation orders have been lifted, residents were asked to leave their homes early in the fire fight as the flames moved closer to homes.
The cause of the Butts fire is under investigation, CalFire officials said.