Experts say little can be done to mitigate immediate danger but urge Joe Biden to take up ambitious, long-term strategy.
Wildfires in the Western United States, including one burning in Oregon that is currently the largest in the US, are creating hazy skies as far away as New York as the huge infernos spew smoke and ash as high as 10km (6 miles) into the air.
In 13 western states, more than 80 large active wildfires have charred 1.3 million acres (526,000 hectares) of drought-parched vegetation in recent weeks, an area larger than the state of Delaware, according to the National Interagency Fire Center (NIFC) in Boise, Idaho.
Several hundred additional fires have burned in western and central Canada, including 86 classified as out of control on Tuesday in the province of British Columbia alone, leading officials there to declare a state of emergency.
Extremely dry conditions and heatwaves 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, experts say.
The jet stream and other cross-continental air currents have carried smoke and ash thousands of kilometres across the US, with people in distant cities feeling the air contamination in their eyes, noses and lungs.
The smoke on the US East Coast was reminiscent of last autumn when multiple large fires burning in Oregon in the state’s worst fire season in recent memory choked the local skies with pea-soup smoke and also affected air quality several thousand kilometres away.
“We’re seeing lots of fires producing a tremendous amount of smoke, and … by the time that smoke gets to the eastern portion of the country where it’s usually thinned out, there’s just so much smoke in the atmosphere from all these fires that it’s still pretty thick,” David Lawrence, a meteorologist with the National Weather Service told the Associated Press news agency.
“Over the last two years we’ve seen this phenomenon,” Lawrence said.
Heavy exposure to wildfire smoke has been linked to long-term respiratory consequences for firefighters, including a sharply elevated risk of developing asthma, according to a University of Alberta study released this week.
The general population also faces severe health effects.
“Wildfire smoke exposure … increases susceptibility to respiratory infections including COVID, increases severity of such infections and makes recovery more difficult,” federal air resource adviser Margaret Key told the Reuters news agency.
Western wildfires enter third week
The wildfires themselves posed a more direct risk to life and property.
Oregon’s Bootleg Fire grew to 1,595 square kilometres (616 square miles) and has blackened 388,600 acres (157,260 hectares) of desiccated brush and timber in and around the Fremont-Winema National Forest, about 400km (250 miles) south of Portland, since erupting on July 6.
Only three other Oregon wildfires over the past century have burned more territory.
The blaze has destroyed at least 70 homes and another 3,400 were listed as threatened, with an estimated 2,100 people under orders to evacuate or be ready to flee at a moment’s notice.
Incident commander Rob Allen said in his daily report that tinder-dry fuels within the fire zone would “continue to burn and produce smoke for weeks”.
“Fighting this fire is a marathon, not a sprint,” Allen wrote. “We’re in this for as long as it takes to safely contain this monster.”
Fires also grew on both sides of California’s Sierra Nevada.
In Alpine County, the so-called California Alps, the Tamarack Fire caused evacuations of several communities and grew to 158 square km (61 square miles) with no containment. The Dixie Fire, near the site of 2018’s deadly Paradise Fire, was more than 163 square km (90 square miles) and threatened tiny communities in the Feather River Valley region.
Tony Galvez fled the Tamarack Fire on Tuesday with his daughter at the last minute and found out later that his home was gone.
“I lost my whole life, everything I’ve ever had. The kids are what’s going to matter,” he told the Associated Press as he fielded calls from relatives. “I got three teenagers. They’re going to go home to a moonscape.”