Lower winds and better weather have helped firefighters battling the United States' largest wildfire in southern Oregon, but gusty winds have prompted evacuations as blazes burn across the West.
Oregon's Bootleg Fire grew to 1600 square kilometres but authorities said higher humidity and better conditions overnight had allowed crews to improve fire lines.
The Oregon fire, which was sparked by lightning, has ravaged the sparsely populated southern part of the state and had been expanding by up to six kilometres a day, pushed by strong winds and critically dry weather.
The blaze, which is being fought by more than 2200 people, is more than one-third contained.
On Thursday, authorities said at least nine people working the fire had tested positive for COVID-19.
At least 2000 homes were ordered evacuated during the fire, and an additional 5000 homes were threatened. At least 70 homes and more than 100 outbuildings have burned, but no one is known to have died.
Meanwhile the Tamarack Fire south of Lake Tahoe had burned more than 200 square kilometres of timber and head-high chaparral in national forest land. It erupted on July 4 and was one of nearly two dozen blazes sparked by lightning strikes.
Windy conditions were hampering more than 1200 firefighters on Thursday battling the Alpine County blaze. It has destroyed at least 10 buildings.
Meanwhile, Oregon on Wednesday banned all campfires on state-managed lands.
Extremely dry conditions and recent heat waves tied to climate change have made wildfires harder to fight.
Climate change has made the West much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive.