Thousands of people have evacuated their homes across parts of the Canadian provinces of Saskatchewan and Manitoba, where officials have declared a state of emergency and crews are working to contain dozens of out-of-control wildfires.

The smoke has already spread to the upper Midwest of the United States and is expected to last through the first few days of June as multiple rounds of smoke are set to blow south, Minnesota’s Pollution Control Agency warned.

The fires are intensifying, and two people were killed after a small town in Manitoba was engulfed in flames. Their deaths represented an ominous start to Canada’s wildfire season, which usually runs from March until October. Here’s what to know.

Where are the wildfires burning?

About 1.7 million acres have burned across both Saskatchewan and Manitoba, according to the Canadian Interagency Forest Fire Centre. Manitoba’s out-of-control wildfires are largely burning on its northwest border with Saskatchewan. In Saskatchewan, the fire activity is also mostly concentrated in the north.

About 17,000 people were ordered to leave and more communities can expect the same in the coming days, said Wab Kinew, the premier of Manitoba. Evacuations across those sparsely populated rural regions in Manitoba, home to several First Nations reserves, were assisted by the Canadian armed forces in cases where the conditions were more dangerous.