Two wildfires burning in the western United States – including one that has become a “mega-fire” on the North Rim of the Grand Canyon – are so hot that they are spurring the formation of “fire clouds” that can create their own erratic weather systems.

In Arizona, the wind-whipped wildfire that destroyed the Grand Canyon Lodge is 9% contained and has charred more than 164 sq miles (424 sq km) to become the largest fire now burning in the continental US and one of the top 10 largest in recorded Arizona history. Getting around it would be roughly like driving from New York City to Washington DC.

Another large fire in