A state of emergency has been declared in California as wildfires ravage its iconic coastline along the Pacific Coast Highway at Big Sur.
National parks in the area were closed earlier on Tuesday in the area surrounding Monterey Bay.
The park shutdowns came as a fire that started Friday just north of Big Sur grew to 78 square kilometres but was just 10 per cent contained.
Twenty homes have burned in the zone, residents of 300 more were ordered to evacuate and more than 2,000 firefighters were trying to douse the blaze.
"At any point in time this fire can change directions, can spread very quickly and if that happens there could be embers that fly a mile ahead of the main fire," said Richard Cordova, a state fire captain.
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Park roads, trails and camping sites in five parks and a nature reserve were closed as a safety precaution because of thick smoke causing unhealthy air quality and to keep the roads free of traffic for firefighters.
Authorities said they had managed to contain 25 per cent of the area, meaning the flames there had been isolated and were not expected to spread.
"We're not really out of the woods," said U.S. Forest Service spokesman Justin Correll.
"We're not ready to relax. There's still a lot of firefighting to do."
Some neighbourhoods in Santa Clarita, population about 200,000, remained off limits because of the fire but most evacuations ordered for about 10,000 homes with an estimated 20,000 residents were lifted.
In Wyoming, a large back country wildfire in the Shoshone National Forest put about 290 homes and guest ranches at risk.
The Wyoming fire in a remote region burned nearly 28 square kilometres and forced the evacuations of 900 people but no homes had burned by Tuesday afternoon, authorities said.
