The fire in Grand Canyon National Park has grown to more than 100,000 acres amid dry weather and a weak monsoon season in Arizona.

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