A satellite image of the eastern United States shows swirling clouds of smoke from wildfires and haze enveloping large portions of that region.

Smoke moved into portions of northern New York State and Vermont on Tuesday. In the Upper Midwest, air quality alerts were issued in Minnesota.

Hundreds of wildfires continued to blaze on Tuesday across Canada, exacerbating an already active wildfire season that was only expected to worsen, and sending smoke into portions of the United States, creating poor air quality levels.

In Ontario, a layer of haze enveloped parts of Ottawa and Toronto, where Canadian officials warned residents about the poor air quality, as smoke moved into portions of northern New York State and Vermont. All of New York City was under an air quality alert on Tuesday because of the smoke; by the afternoon, the Manhattan skyline was obscured by hazy skies.

There were more than 400 active wildfires in Canada on Tuesday, according to the Canadian Interagency Forest Fire Centre, with more than 200 deemed to be “out of control.”

In eastern Canada, Quebec was most affected by wildfires as of early afternoon on Tuesday, with more than 150 active blazes across the area, according to the fire agency. Residents in some areas were being encouraged to close their windows and doors, local officials in Quebec said.

Videos and images showed some fires blazing for miles, sending dark smoke plumes billowing into the sky.

Burned-area boundaries and hotspot locations are estimates based on satellite data, and hotspots indicate likely areas of burning detected within the previous two days. By Martín González Gómez and Madison Dong

At a press conference on Monday, Prime Minister Justin Trudeau said he was in contact with local officials across Canada about the fires.

“This is a scary time for a lot of people,” Mr. Trudeau said.

As of Monday, an estimated 26,000 people across Canada had been evacuated from their homes because of wildfires, Bill Blair, Canada’s minister of public safety, said at the press conference.

“The images that we have seen so far this season are some of the most severe ever witnessed in Canada,” Mr. Blair said.

A woman in an orange hoodie walks her dog along a grassy bank of the Ottawa River, and smoke obscures part of the background on the river’s opposite side.

Many Canadians who have had to evacuate in recent days had just a few hours to pack before fleeing their homes, Mr. Trudeau said.

“When people lose their homes, they don’t just lose a roof and their possessions,” Mr. Trudeau said. “They lose a special place where they saw their children grow up, where they built a life for themselves. This is incredibly difficult and heartbreaking.”

Bands of smoke from the numerous wildfires were expected to shift southward across the border on Tuesday, creating hazy skies and prompting the U.S. National Weather Service to issue air quality alerts for parts of the upper Great Lakes and the Northeast.

Large swaths of Minnesota were under air quality alerts through the evening on Tuesday, the Weather Service said. Light winds were expected to push smoke from wildfires in Quebec across Minnesota. Smoke was also predicted to move into the state off Lake Superior.

Weather officials warned that people more sensitive to poor air quality, such as people with lung disease and heart disease, children, and older adults, should limit certain activities outdoors.

Farther east, air quality alerts were also in place for multiple counties in upstate New York and New York City through midnight. Similar alerts were issued for parts of Connecticut, Massachusetts, and Vermont.

Satellite images of North America on Tuesday showed light brown smoke streaming south from the fires. The smoke appeared to be particularly thick over portions of Quebec, Ontario, and New York. Hazy.