Wildfires burning out of control across the Western United States brought smoke-filled skies to New York City and Washington DC on Tuesday.
The National Weather Service (NWS) said smoke and haze from the Bootleg Fire in Oregon that had drifted across the Great Lakes region had reached the Eastern Seaboard.
“This will filter the sunshine here throughout the day today,” the NWS said on Twitter.
The smoke blankets partially blocked the sunrise in New York on Tuesday, weather watchers reported, and when the sun eventually became visible it had a distinctive reddish hue.
New York State’s Department of Environmental Conservation issued a rare air quality alert for parts of upstate New York including the Finger Lakes and Rochester.
It recommended older adults, young children, and anyone with underlying conditions should stay indoors.
Similar warnings were in effect for much of Canada, as well as from Vermont to northern New York state until midnight Tuesday, the NWS said.
Accuweather Senior Meteorologist Carl Erickson told the New York Post the smoke would pass at a high enough altitude of 10-20,000 feet above New York City that there was little to no risk to air quality.
“It could be some rather beautiful, enhanced, vibrant sunsets tomorrow evening just because of that smoke,” he told the newspaper.
The smoke, which stretched as far south as Washington DC, was likely to remain visible until a cold front sweeps through later in the week.
The hazy skies are the result of some 80 wildfires currently burning across 13 states that have already destroyed more than 1 million acres of forest and farmland, CNN reported.
Montana and Idaho account for 35 of the fires, which are aided by a heatwave that has brought searing temperatures and dangerous conditions for firefighters.
The largest single blaze, the Bootleg Fire, has scorched around 350,000 acres, or 530 square miles, of forest and grasslands, with thousands of firefighters battling through extreme forms of weather generated by the blaze.
As the smoke builds, it becomes caught up in weather systems and transported across the country.
The extreme conditions are also creating “fire clouds” of smoke and ash that are able to form “fire whirls” and tornadoes, as well as fierce winds and lightning.
The Associated Press reported the fire clouds, also known as Pyrocumulus clouds, look like giant, dirty-coloured thunderheads that sit atop a massive column of smoke coming up from a wildfire. Often the top of the smoke column flattens out to take the shape of an anvil.
“When air over the fire becomes super-heated, it rises in a large column. As the air with more moisture rises, it rushes up the smoke column into the atmosphere, and the moisture condenses into droplets. That’s what creates the “fire clouds” that look much like the thunderheads seen before a big thunderstorm,” the Associated Press reported.