BLY, Ore. (AP) -- Firefighters in Oregon reported good progress in the battle against the nation's largest wildfire, while authorities canceled evacuation orders near a major blaze in Northern California and another on Hawaii's Big Island.
Containment of the Bootleg Fire in remote southern Oregon was up to 84% late Sunday. It was 56% contained a day earlier.
"That reflects several good days of work on the ground where crews have been able to reinforce and build additional containment lines," fire spokesman Al Nash said.
The blaze has scorched over 646 square miles (1,673 square kilometers) since being sparked by lightning July 6 in the Fremont-Winema National Forest.
California's Dixie Fire covered nearly 388 square miles (1,005 square kilometers) in mountains where 42 homes and other buildings have been destroyed.
The fire was 33% contained Sunday evening, and evacuation orders and warnings had earlier been lifted for several areas of Butte and Plumas counties.
The cause of the blaze was still under investigation.
Authorities warned that with unpredictable winds and extremely dry fuels, the risk of flare-ups remained high.
In recent days, lightning sparked two wildfires that threatened remote homes in the Shasta-Trinity National Forest. Evacuation warnings remained in place Sunday for communities along the Trinity River.
In Montana, a wind-driven wildfire destroyed more than a dozen homes, outbuildings and other structures, authorities said Sunday. Evacuations were ordered after flames jumped a highway and moved toward communities near Flathead Lake in the northwestern part of the state.
Crews also battled major blazes in northeast Washington and northern Idaho.
Nearly 22,000 firefighters and support personnel were battling 91 large, active wildfires covering 2,813 square miles (7,285 square kilometers) in mostly western states, the National Interagency Fire Center said.
A historic drought and recent heat waves tied to climate change have made wildfires harder to fight in the American West. Scientists say climate change has made the region much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive.
The U.S. Drought Monitor reported last week that while a robust monsoon has delivered drought-easing rainfall to the Southwest, critically dry conditions persist across Northern California and the Northwest, where there has been an expansion of "exceptional drought," the worst category.
Dry conditions and powerful winds made for dangerous fire conditions in Hawaii. A wind advisory was issued Sunday for portions of Lanai, Maui and the Big Island.
A fast-moving wildfire on Hawaii's Big Island grew to 62.5 square miles (101 square kilometers), prompting mandatory evacuation orders. Those orders -- which forced thousands of residents out of their homes -- were lifted Sunday evening. However, authorities told residents to remain alert.
"County officials ask all residents of the affected areas to only return home if absolutely necessary," Hawaii County spokesperson Cyrus Johnasen said in a statement. "Smoke and other conditions may make returns unsafe for those with prior and underlying respiratory conditions."
Local media reported at least two homes had been destroyed. Two community shelters were open for residents who weren't able to return home, the Hawaii Red Cross said.