Wildfires can burn and spread differently depending on what vegetation they burn. The two fires in northern Arizona have varied landscapes. Ponderosa pine trees grow near the North Rim of the Grand Canyon and can live for hundreds of years.

Gov. Katie Hobbs questioned why the U.S. government decided to manage the Dragon Bravo fire, which started with a lightning strike, as a “controlled burn” during the height of the summer.

As of Monday, the Dragon Bravo fire on the North Rim had consumed more than 5,700 acres and was not contained, according to the U.S. Forest Service.

A mix of high temperatures, gusty winds, low humidity, and dry vegetation has fuelled the fire's swift advance in Arizona, officials say.