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.
Smoke dangers
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.
