Six members of an elite firefighting crew battling blazes dotting northern Nevada were caught in a fiery dust devil that burned two so severely they had to be flown to a Las Vegas hospital, fire officials said.

The fire whorl formed in live embers as the crew was burning off vegetation to prevent a nearly five-square-mile fire from spreading, the Bureau of Land Management said.

Both hospitalized firefighters had first- or second-degree burns over 50 percent of their bodies but were expected to recover, public information officer Frank Mosbacher said Thursday. A federal interagency serious-accident team was investigating.

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The blaze was one of more than a dozen lightning-sparked fires that have blackened more than 110 square miles of Nevada in the past week. The state's largest fire had reached more than 65 square miles near the Big Rocks Wilderness.

In California, firefighters who have been battling a 25-square-mile blaze in the Cleveland National Forest, east of San Diego, for five days had the fire about a quarter contained.

With lessening heat and calmer winds, the fire's front died down and firefighters could work close to smoldering areas, said Roxanne Provaznik of the California Department of Forestry.

Western Montana fire crews were aided by helicopters and air tankers as they tried to keep a fast-growing wildfire from reaching at least a dozen homes. The blaze, which started east of Florence on Tuesday, had already destroyed one trailer house and forced the evacuation of about a dozen other homes, fire information officials said.

In Oregon, a fire that had burned nearly 14 square miles at the southern edge of Oregon's Wallowa Mountains was threatened about 20 buildings. Most of Oregon's wildfires were in grazing land, the largest reaching 107 square miles in the southeastern corner of the state.

The firefighters injured Tuesday in Nevada were all members of the Eldorado National Forest Hotshot crew based near Placerville, Calif. The two men hospitalized, Jesse Shirley, 27, of California and Jeff Gelhausen, 32, of Colorado, were in fair condition, Mosbacher said.