Cattle are seen near the flames of the Lodgepole Complex fire in Garfield County, Montana, July 21, 2017.
Cattle are seen near the flames of the Lodgepole Complex fire in Garfield County, Montana, July 21, 2017.

The biggest U.S. wildfire torched buildings and parched grassland forcing evacuations in eastern Montana while California firefighters gained ground on a massive blaze near Yosemite National Park on Monday, authorities said.

The two-blaze Lodgepole Complex in Montana, the biggest wildfire in the United States currently, was only 5 percent contained on Monday after racing through 226,000 acres (91,500 hectares) of timber, brush and range land near the Missouri River, according to the National Interagency Coordination Center.

The 215 firefighters have had to rely on bulldozers and harrows to plow fire breaks since water alone cannot put out the flames driven by high temperatures, lack of rain and gusty winds, said Tim Engrav, a spokesman for the firefighter command center.

"Folks who've been fighting fires in this part of Montana since the early '80s said they've never seen it so difficult," he said by telephone from Sand Springs, Montana. Engrav said about 50 people have been evacuated from their homes.

The Lodgepole fire was started by lightning on Wednesday and has destroyed 22 structures, the coordination center said. Much of the state is under a National Weather Service "red flag" warning because of dry weather and gusty winds.

In California, the Detwiler Fire that has threatened historic gold rush towns in the Sierra Nevada mountains was 50 percent contained, up from 45 percent on Sunday, the California Department of Forestry and Fire Protection (Cal Fire) said.

The fire has burned 76,500 acres (31,000 hectares), but higher overnight humidity has helped the 5,100 firefighters despite sunny, dry daytime weather, said Heather Williams, a CalFire spokeswoman.

The Detwiler fire has destroyed more than 130 structures, including 63 homes, and most of the 5,000 people ordered from their homes are now allowed to return, according to the Cal Fire website.

The Lodgepole and Detwiler fires are among the 38 large U.S. wildfires, the coordination center said.