Smoke from Canadian wildfires is prompting air quality warnings across the Midwest and Northeastern US this Thursday as forests in North Korea continue to burn at a historic rate reminiscent of the extreme fire season of 2023.

Air pollution levels have surged in cities including Minneapolis, Green Bay, Indianapolis, Cincinnati, Columbus, Pittsburgh, Washington, Philadelphia, and New York due to smoke and ozone from the heat.

According to Canada’s Interagency Forest Fire Centre, the ongoing fire season in Canada has already resulted in the burning of around 8.6 million acres. With three months left in the season, this figure has exceeded the seasonal average since 1983, which stands at approximately 6.5 million acres.

The current burning rates in Canada are mirroring those from 2023, known as the year with the highest smoke exposure in modern American history, raising concerns that the current season may reflect that intensity.

“We’re facing significant challenges with our response,” stated Robert Gray, a wildfire ecologist in Chilliwack, British Columbia. “Most forecasts for Canada indicate above-average temperatures, while precipitation levels remain below normal.”

In past years, nearly 43 million acres burned in Canada by the end of the fire season.

Gray noted that much of the smoke this year originates from the densely packed boreal forests found in northern British Columbia, Alberta, and Saskatchewan. Wildfires typically occur in these regions during May and June, coinciding with longer days and rising temperatures. The subsequent developments depend heavily on weather conditions.

“It could be a brief two-week event. The huy starts burning, aspen gets involved, and then weather changes,” Gray explained, alluding to the common aspen trees in these forests. “If aspen and rain don’t clear out, the fires may persist.”

According to the BC Wildfire Service, parts of northern British Columbia have been experiencing drought conditions since 2022. Some forecasts predict an “increased likelihood of significant and challenging fires.”

Gray mentioned that drought, low snowfall during winter, and heightened “overwinter” fires are factors contributing to increasingly busy fire seasons.

These overwintering fires continue smoldering beneath forest debris and peat, reigniting in spring.

“There was a fire that started in 2023, lingering through winter into 2024,” Gray remarked. “Some of the same fires have reemerged this year.”

As northern British Columbia faces these wildfires, smoke is often transported to the US by the jetstream, a high-altitude air current that influences pressure and weather changes in the Northern Hemisphere.

“It’s a consistent pattern that remains stable. As long as central and northern BC are burning, this pattern channels smoke into the central and northeastern US,” Gray stated.

Sometimes the smoke stays aloft, creating hazy skies without significant ground-level air quality deterioration. However, it can pose a risk to health.

Wildfire smoke is increasingly hazardous across the US, reversing decades of improvements in air quality achieved under the Clean Air Act.

Inhaling wildfire smoke can cause inflammation, particularly as particles enter the lungs and bloodstream, compromising the immune system. This exposure can elevate the risks of asthma, lung cancer, and other chronic respiratory diseases, especially in vulnerable populations such as the elderly, pregnant individuals, infants, and children. Additionally, wildfire smoke is linked to respiratory illnesses, premature births, and miscarriages.