Canada’s Burning Forests: Inside The Hidden Forces Behind America’s Smoky Summers

Canada has experienced some of the largest wildfire seasons ever recorded in recent years, and the smoke does not stop at the border. Driven by winds thousands of feet above the ground, thick plumes have repeatedly spread into the northeastern United States, turning the sky orange, reducing visibility, and causing unhealthy air for tens of millions of people. A fire burning hundreds of miles away can still affect cities from Minnesota to Maine within a day or two.

While wildfires are nothing new in Canada, the scale has changed. Canada has about 857 million acres of forest, nearly 9% of the world's forests, much of it remote and difficult to reach. Decades of putting out smaller fires in some regions allowed dead trees and brush to build up, while insect outbreaks killed millions of acres of forest. Combined with longer periods of hot, dry weather and strong winds, fires can now spread farther and produce far more smoke. Controlled burns and logging help reduce fuel, but only a small portion of Canada's vast forests can be actively managed each year. This is why smoke reaching the northeastern U.S. has become much more common in recent years.

In 2023, Canada recorded its worst wildfire season in modern history. More than 6,500 wildfires burned about 45 million acres, over 70,000 square miles, an area larger than Florida. Nearly 250,000 people were forced from their homes during the season. Smoke crossed much of North America and even reached Europe. On June 7, 2023, New York City briefly recorded the worst air quality of any major city in the world as thick smoke covered the skyline. Air quality readings climbed above 400 in parts of the city, a level considered hazardous.

The pattern continued in 2024, and major wildfire outbreaks again sent smoke into the United States. Fires spread across provinces including Manitoba, Saskatchewan, Alberta, British Columbia, and Ontario. During several events, smoke stretched more than 2,000 miles across the continent. The fine particles carried in wildfire smoke are small enough to travel deep into the lungs and can increase health risks. Children, older adults, and people with heart or lung conditions face the greatest danger, but even healthy adults can experience coughing, burning eyes, headaches, and breathing problems during heavy smoke events.

Lightning starts many Canadian wildfires, especially in remote forests, but people also cause fires through unattended campfires, equipment, power lines, and discarded cigarettes. Once flames reach thick evergreen forests or peat rich ground, they can burn for weeks or months. Some fires continue smoldering underground through winter and can restart the following year.

Canada's forests are one of the largest natural landscapes on Earth, but their size creates a major challenge. Many fires are too remote to attack immediately, forcing crews to focus on protecting communities, roads, and critical infrastructure. Smoke often becomes the biggest threat far beyond the flames themselves.

For millions across the Northeast, the danger is often invisible until the sky turns gray and the smell of smoke fills the air.  As Canada's fire seasons grow larger, Americans hundreds of miles away are learning that the next smoky sunrise may begin with a lightning strike in a different country thousands of miles away.