The fire has burned for a month on the North Rim of the Grand Canyon, destroyed historic buildings and called for thousands of fire personnel.

Pyrocumulus clouds, otherwise known as flammagenitus or “fire clouds,” develop due to “convection initiated by heat from forest fires, wildfires or volcanic eruption activity,” according to the World Meteorological Organization.

The Grand Canyon has been on fire for a month, as crews continue to battle the continental United States' largest wildfire this year.