Why were the sun and moon red on Tuesday? Wildfire smoke – here’s how to recolor the sky

People in New York City and across the Northeastern United States woke up Tuesday morning to an unusual sight. Depending on the time, the early risers reported seeing either the moon or the sun taking on a reddish glow. It wasn’t the first time in recent weeks that the sun and moon have turned red in the sky over various parts of the Pacific Northeast and Northwest, as wildfires burning in eastern and western Canada continue to send smoke across the border.

Canada is experiencing one of its worst wildfire seasons on record, officials said during a news conference last week, with more than 6.7 million acres already burned since the start of the year. The fires are particularly intense right now in the eastern provinces of the country, with wildfires raging in Quebec and Nova Scotia forcing nearly 14,000 people to evacuate, CBC News mentioned.

Winds are circling a steady low-pressure system that hovers over the eastern provinces of New Brunswick, Nova Scotia and Prince Edward Island, known as the Canadian Maritimes, and is driving smoke from wildfires toward the northeastern U.S. Matt Sitkowski, chief science editor for The Weather Channel, tells CBS News Tuesday.

Sitkovsky said the smoke causes the sun and moon to appear red behind a hazy, gray sky. Since the color of the sky is determined based on how sunlight interacts with the number and size of particles in the air, it changes as smoke escapes, introducing more particles into the atmosphere.

“The sky is blue, for example, because small particles in the atmosphere scatter short wavelengths of the visible light spectrum more strongly than long wavelengths,” Sitkovsky said, noting that blue-tinged light has shorter wavelengths while red-tinged light has longer wavelengths. .

“When smoke is in the atmosphere, it not only makes the sun dimmer, but increases the amount and size of particles in the atmosphere that absorb more of the shorter wavelengths, letting longer wavelengths reach our eyes,” he explained.

Why is there an air quality alert?

The sun and red moon over the northeastern US states this week brought a series of air quality alerts that affected millions of people on Tuesday, some of whom live as far west as Ohio and Missouri and as far south as North Carolina.

air quality The health advisory was valid For most of New York state, according to the New York State Department of Environmental Protection, which said affected areas include the New York City metropolitan area, the lower Hudson Valley, the upper Hudson Valley, the Adirondacks, eastern Lake Ontario, and central regions. Alerts were also effective in parts of Delaware, Maryland, MassachusettsPhiladelphia and much of North Carolina, as well as in Columbus and St. Louis.

Officials said the air quality was considered “unhealthy for sensitive groups” in the places where the alerts were issued on Tuesday, but that they likely wouldn’t harm the general public. Sensitive groups, including the elderly and children, as well as people with asthma and other pre-existing respiratory diseases, are encouraged to limit strenuous outdoor activity for extended periods while the health advice is active.

In general, the Air Quality Index measures pollution by the amount of fine, solid and liquid particulate matter present in a given airspace, and weather authorities have recognized that the pollution that occurred on Tuesday is linked to the plume of smoke, at least. 100 wildfire Burn across the border in Quebec and Ottawa.

“Air quality has deteriorated across much of the Northeast as smoke from wildfires in Canada moves south,” the National Weather Service wrote in the National Weather Service. tweet. “Poor air quality can be dangerous. Before spending time outside, check the air quality forecast. Make sure you’re not doing yourself more harm than good.”

Officials expect winds to continue blowing smoke from the Canadian wildfires northeast through Wednesday at the earliest. The Midwest suffered similar consequences from the wildfires across the border earlier in the week, the Minnesota Pollution Control Agency said in a statement tweet Monday that “a band of smoke from the wildfires in Quebec will continue to spread across east-central and southeastern Minnesota today due to very light winds.”

What is the reason for the outbreak of fires in Canada?

There were 413 active wildfires across Canada as of Sunday. CBC News reported, citing federal officials such as Michael Norton, an official with Natural Resources Canada, who said earlier this week that it was unusual for the country to see such a large spread of wildfires from coast to coast at this time of year. Norton said wildfires in Canada are usually triggered by lightning, though human-caused fires have spawned more serious fires as well.

The map below, created by CBS affiliate radio station KDKA on Tuesday afternoon, shows the widening plumes of smoke currently emanating from wildfires in Canada entering the United States.

“Wildfire smoke can travel thousands of miles and stay in the air for days,” Sitkowski said. “How the smoke is dispersed is a function of the larger weather pattern,” as is wind direction and strength. “Smoke is also present at different levels of the atmosphere, and the greatest danger to our health is when it is closest to the ground.”