Western wildfires

Fire consumes trees along U.S. highway 120 as the Rim Fire burns out of control in Buck Meadows, Calif., Aug. 21, 2013.

The Rim Fire continues to burn out of control outside of Yosemite National Park. It is one of more than 50 major brush blazes burning across the western U.S.

Read more: Yosemite-area wildfire growing at alarming rate

Beaver Creek Fire

Members of the media walk through part of the 104,457 acre Beaver Creek Fire in the Baker Creek area north of Ketchum, Idaho, Aug. 19, 2013.

Rim Fire

The sun sets through heavy smoke from the Rim Fire in Groveland, Calif., Aug. 21, 2013.

Government Flats Complex fire

The Government Flats Complex fire burns south of The Dalles, Ore., Aug. 18, 2013.

Rim Fire

The Rim Fire burns near Yosemite National Park, Calif.

Rim Fire

Firefighters from Cosumnes Fire Department monitor a back fire while battling the Rim Fire in Groveland, Calif., Aug. 22, 2013.

Rim Fire

The Rim Fire burns near Groveland Ranger Station in Groveland, Calif.

Government Flats Complex fire

The Government Flats Complex fire flares up south of The Dalles, Ore., Aug. 18, 2013.

Rim Fire

An air tanker drops fire retardant on a ridge ahead of the advancing Rim Fire, Aug. 22, 2013 in Groveland, Calif.

Beaver Creek Fire

Firefighters with the private contract company Great Basin Fire, mop up part of the 104,457-acre Beaver Creek Fire in the Baker Creek area north of Ketchum, Idaho, Aug. 19, 2013.

Rim Fire

Fire consumes trees along U.S. highway 120 as the Rim Fire burns out of control in Groveland, Calif., Aug. 21, 2013.

Beaver Creek Fire

The 104,457-acre Beaver Creek Fire burns in the Baker Creek area, north of Ketchum, Idaho, Aug. 19, 2013.

Beaver Creek Fire

Members of the media walk through part of the 104,457-acre Beaver Creek Fire in the Baker Creek area, north of Ketchum, Idaho, Aug. 19, 2013.

Rim Fire

A television news crew uses a back fire as a backdrop for a live shot while reporting on the Rim Fire in Groveland, Calif., Aug. 22, 2013.

Beaver Creek Fire

Firefighters with the private contract company Great Basin Fire, mop up part of the 104,457-acre Beaver Creek Fire in the Baker Creek, north of Ketchum, Idaho, Aug. 19, 2013.

Government Flats Complex fire

The Government Flats Complex fire burns south of The Dalles, Ore., Aug. 18, 2013.

Rim Fire

Firefighters monitor the Rim Fire in Froveland, Calif., Aug. 22, 2013.

Rim Fire

A U.S. Forest Service firefighter monitors the Rim Fire in Groveland, Calif., Aug. 22, 2013.

wildfire, yosemite, rim fire — AP Photo/Jae C. Hong

Inmate firefighters walk along Highway 120 as firefighters continue to battle the Rim Fire near Yosemite National Park, Calif., on Sunday, Aug. 25, 2013. Fire crews are clearing brush and setting sprinklers to protect two groves of giant sequoias as a massive week-old wildfire rages along the remote northwest edge of Yosemite National Park.

A firefighter watches for spot fires during a burnout operation while battling the Rim Fire near Yosemite National Park, Calif., on Sunday, Aug. 25, 2013. Fire crews are clearing brush and setting sprinklers to protect two groves of giant sequoias as a massive week-old wildfire rages along the remote northwest edge of Yosemite National Park.

Calif. residents prepare for approaching wildfire

A wildfire is threatening more than 4,500 homes in California - about half of which are in Pine Mountain Lake - from a fire that ranks among the 20 worst the state has ever seen.