The Line Fire burning in California created dark pyrocumulus clouds, followed by lightning.
The Line Fire in California is burning so fiercely that it’s creating its own weather, CNN Fire clouds, or pyrocumulus clouds, formed above the fires earlier this week as the Landsat-8 high-resolution weather satellite, a joint data collection vehicle of NASA and the United States Geological Survey (USGS), observed from hundreds of kilometers above the ground.
Fire clouds form over intense heat sources, such as forest fires or volcanic eruptions. The air above these heat sources is forced upward rapidly and turbulently, causing moisture in the air to condense, forming clouds.
However, the fire clouds also absorb a lot of smoke and ash from the fires below, making them much darker than the typical white cottony clouds. The Line Fire has pushed smoke and ash thousands of feet into the air. In satellite images, the fire clouds look like bombs exploding. While the cumulus clouds to the east of the fires are white and fluffy, the fire clouds are surrounded by light brown or tan smoke.
The fire cloud in the Line Fire then developed into a pyrocumulonimbus cloud that produced lightning and rain, NASA said. Rain from such a thunderstorm could aid firefighting efforts, but strong winds and additional lightning strikes in the dry region could spark new fires.
The Line Fire broke out on September 5, starting in the foothills of the San Bernardino National Forest and spreading. As of September 12, the fire had burned more than 35,000 acres and was only about 21% contained. The disaster forced thousands of people to evacuate, damaged many structures, and injured several people.
Firefighters have been struggling to contain the blazes over the past week due to challenges including hot, dry conditions combined with steep, rugged terrain. Smoke from the fires creates clouds that are accompanied by thunderstorms. These wildfire-induced thunderstorms have increased wind speeds, fanning the flames and causing them to spread.
More than 3,000 firefighters are battling the Line Fire. “The fire behavior on this fire — based on the information we’re getting from our fire partners — is very unusual, and ‘atypical’ in fire science, as I’ve been told. We’re constantly moving and being flexible,” said San Bernardino County Sheriff Shannon Dicus.