Canada is battling one of its most severe wildfire seasons on record, with new blazes erupting across western provinces while dozens of fires continue to burn in Ontario.

Nearly 34,000 lightning strikes over the past few weeks sparked multiple wildfires in southern British Columbia, where officials have reported over 90 active fires and 25 evacuation orders. Authorities warned that rising temperatures and dry weather are expected to fuel existing fires.

“The weather forecast is far from favorable. There is no significant help from Mother Nature whatsoever in the foreseeable future,” said Incident Commander Hugh Murdoch, who is overseeing a cluster of fires near Kimberley, British Columbia.

Prime Minister Mark Carney described the current season as one of Canada’s most intense on record, announcing that the federal government will deploy more than 5,300 firefighters alongside about 300 water bombers, helicopters and evacuation aircraft. He also confirmed that Mexico will send up to 200 firefighters to assist in the coming weeks.

Thousands of residents, including members of several First Nations communities, have already been evacuated. So far, wildfires have scorched about 2.95 million hectares (7.29 million acres), surpassing the 10-year average of roughly 2.55 million hectares. Canada also has more active wildfires than it did at the same point in either of the previous two years.

Ontario remains a major hotspot, the area continues to face one of the country’s biggest wildfire challenges, with 139 active fires reported across the province’s northwest region. Officials said 32 of those fires remain out of control.

Meanwhile, Environment Canada has issued air quality warnings for Banff, Alberta, and nearby communities because of wildfire smoke, although conditions are reportedly improving over the past few days.

Eastern Canada has seen some relief. Favorable weather, combined with support from firefighters from neighboring provinces, France and the United States, has helped Quebec contain several fires.

“The situation in Quebec is under control. We have good weather to help us,” said Stéphane Caron of Quebec’s forest fire prevention agency, SOPFEU. “We have to make sure that there’s no hotspot on the ground anymore because if there’s hot weather and no rain, the fire can be back.”

Smoke blankets parts of the United States. Smoke from the Canadian wildfires has drifted hundreds of miles south, leading to hazardous air quality across several US states.

Minnesota, Wisconsin and Michigan are experiencing some of the worst conditions, while millions more in cities including Philadelphia, New York City and Baltimore have also been affected.

Scientists say climate change is contributing to more frequent and intense wildfire seasons by creating hotter, drier conditions that allow vegetation to ignite more easily.

“The frequency and intensity of these wildfire smoke events are increasing,” said Dan Westervelt, an associate research professor at Columbia University’s Lamont-Doherty Earth Observatory. He warned that such events are becoming a recurring feature rather than isolated incidents. Health experts warn of smoke risks.

Health experts say wildfire smoke poses serious health risks because it contains microscopic particles that can penetrate deep into the lungs and even enter the bloodstream.

Dr. David Eisenman, a professor of medicine at the David Geffen School of Medicine at UCLA, said research links wildfire pollution to increased cases of heart attacks, heart failure, stroke and respiratory illnesses. Long-term exposure has also been associated with pregnancy complications and possible developmental disorders in children.

“These are going to be repeated events … and a lot of what they are producing is invisible,” Eisenman said. “Even if the sky is not brown, it still might be toxic for you.”

He urged people to monitor local air quality reports, limit outdoor activities during smoky conditions and wear an N95 mask if they must go outside.

The Environmental Protection Agency also recommends using air purifiers, creating a “cleaner air room” at home and stocking up on food and medication to reduce the need to venture outdoors during periods of poor air quality.