Lightning, which is more common in hotter temperatures, is usually the cause of wildfires that burn the most land. In 2023, scientists at Canada’s natural resources department found that lightning sparked fires that burned 93 percent of the total wildfire area, and the remaining seven percent of the area burned from human causes.

A gray haze from wildfire smoke could be seen in Cincinnati, and the entire state of Minnesota is under an air quality alert.

Plumes of smoke are blanketing large swaths of the U.S. and parts of Europe, presenting risks for those breathing it