BIG SUR, Calif. -- A wildfire burning along California's Big Sur coastline keeps growing a week after it broke out, and looks to be a problem for the scenic region for weeks to come.

Anxious residents driven from their homes awaited word on their properties and popular parks and trails closed at the height of tourist season because of the blaze, one of several large fires burning across western states. As of Thursday, the blaze spanned 42 square miles (109 square kilometres) and was only 10 per cent contained.

The California Department of Forestry and Fire Protection estimated it will take until the end of August to extinguish it.

"Every day the fire is gaining ground on us," Cal Fire Battalion Chief Robert Fish said.

It has destroyed at least 34 homes and put at least 2,000 homes and other buildings at risk.

A 35-year-old father of two girls was killed this week when the bulldozer he was operating rolled over on the fire lines.

On Thursday he was identified as Robert Reagan, a 35-year-old father of two daughters from Fresno County who also helps care for a young niece, according to his sister Hannah Cunnings.

Cunnings said he was the kind of person who would offer to put snow chains on a neighbour's car or fix an engine that needed repair.

"Even since he was a boy, he just really wanted to help people," she said, crying.

Firefighters worked in rugged terrain near State Highway 1 in an area that draws tourists from around the world for the dramatic vistas of ocean and mountains. The famous roadway remained open, but smoke and the threat of flames forced the closure of state parks near Big Sur, a big economic driver for the region.

Tom and Donna Huntington, both 65, have lived for 29 years in the community of Palo Colorado, which was hard-hit by the fire. They fled their home last Friday and have been staying with friends and a Red Cross shelter at a school.

"It's a heartbreaker. I could cry right now," Tom Huntington said. "I'm so lucky I didn't lose my house. And I know some people that have."

Eric Beninger, a former firefighter who also lives in Palo Colorado, isn't sure his home is still standing.

"When I did leave yesterday I ended up seeing flames coming up my road," he said. "Just hope for the best, that's about all I can do."

Four people who escaped the fire early in the week acknowledged growing marijuana in the area for the last three months, Monterey County sheriff's Sgt. Kathy Palazzolo said.

Another man was killed last week in a wildfire still burning on the outskirts of Los Angeles. Crews have stopped the spread of that nearly 60-square-mile (155-square kilometre) blaze, which destroyed 18 homes in mountains and canyons around Santa Clarita.

Authorities have not determined a cause for either California fire.

In Idaho, a wildfire burning timber in rugged terrain crossed a state highway and threatened a backcountry yurt system popular among winter recreationists. The 20-square-mile blaze burning west to east crossed State Highway 21 about 5 miles south of Lowman, officials said.

There are six yurts with a replacement cost of $60,000 each that are booked solid through the winter by cross country skiers, parks officials said.

In Wyoming, favourable weather conditions allowed firefighters to take the offensive Thursday for the first time against a large wildfire threatening seasonal homes in the west of the state. The fire in the Shoshone National Forest northwest of Dubois has burned about 19 square miles.

It has burned up to a rural subdivision area with about 290 seasons homes, but no structures have been lost.