Erratic winds and dry lightning added to dangers for crews battling the largest US wildfire on Monday in parched Oregon forests, just one of dozens burning across several western states.
The destructive Bootleg Fire, one of the largest in modern Oregon history, has burned more than 476 sq miles ((1,210 sq km), an area about the size of Los Angeles. The blaze just north of the California state line was 25% contained.
Meteorologists predicted critically dangerous fire weather through at least Monday with lightning possible in both California and southern Oregon.
“With the very dry fuels, any thunderstorm has the potential to ignite new fire starts,” the National Weather Service in Sacramento, California, said on Twitter.
Thousands were ordered to evacuate, including some 2,000 who live in rugged terrain among lakes and wildlife refuges near the fire, which has burned at least 67 homes and 100 outbuildings.
Climate change has made the US west much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive. Firefighters said these conditions in July are more typical of late summer or fall.
Pyrocumulus clouds – literally translated as “fire clouds” – complicated containment efforts for the Dixie Fire in northern California, where flames spread in remote areas with steep terrain crews can’t easily reach, officials said. New evacuation orders were issued in rural communities near the Feather River Canyon.
The Dixie Fire remained 15% contained and covered 29 sq miles. The fire is north-east of the town of Paradise, California, and survivors of that horrific fire that killed 85 people watched warily as the blaze burned.
A growing wildfire south of Lake Tahoe jumped a highway, prompting more evacuation orders, the closure of the Pacific Crest Trail and the cancellation of an extreme bike ride through the Sierra Nevada.
The Tamarack Fire, which was sparked by lightning on 4 July, had charred about 28.5 sq miles of dry brush and timber as of Sunday night. The blaze was threatening Markleeville, a small town close to the California-Nevada state line. It has destroyed at least two structures, authorities said.
A notice posted on Saturday on the 103-mile Death Ride’s website said several communities in the area had been evacuated and ordered all bike riders to clear the area. The fire left thousands of bikers and spectators stranded.
Kelli Pennington and her family were camping near the town so her husband could participate in his ninth ride. They had been watching smoke develop over the course of the day, but were caught off guard by the fire’s quick spread.
“It happened so fast,” Pennington said. “We left our tents, hammock and some foods, but we got most of our things, shoved our two kids in the car and left.”
About 800 fire personnel were assigned to battle the flames by Sunday night, “focusing on preserving life and property with point protection of structures and putting in containment lines where possible,” the US Forest Service said.
A fire in the mountains of north-east Oregon grew to more than 18 square miles by Sunday. The Elbow Creek Fire that started on Thursday has prompted evacuations in several small, remote communities around the Grande Ronde River about 30 miles south-east of Walla Walla, Washington. It was 10% contained.
Natural features of the area act like a funnel for wind, feeding the flames and making them unpredictable, officials said.
Overall, about 70 active large fires and complexes of multiple blazes have burned nearly 1,659 sq miles in the US, the National Interagency Fire Center said. The US Forest Service said at least 16 major fires were burning in the Pacific north-west alone.