California is burning like hell right now.
And the fires are more visually menacing than usual, thanks to the rare pyrocumulus clouds the flames are creating.
The fires are burning so hot that they’re making their own pyrocumulus cloud systems, each up to five miles high. These clouds are also making firefighting efforts more difficult.
And more frightening, these clouds look like there was a giant volcanic eruption somewhere in the Golden State – and there are plenty of dangerous volcanoes around: Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, Hubehebe Craters, and Salton Buttes.
Formation of pyromuculus clouds
Normal clouds are formed when the sun heats the earth’s surface, causing water to evaporate and rise into the atmosphere, where it cools and condenses into a cloud.
This is a relatively slow process compared to the formation of a pyrocumulus cloud, where the intense heat of a huge wildfire burns the moisture out of the vegetation. This moisture then accumulates on smoke particles and rapidly condenses as it rises.
Pyrocumulus clouds are more commonly seen above volcanic eruptions, which produce lots of steam. If you’ve ever seen an evil-looking cloud creating dry lightning above a volcano, that’s a pyrocumulus cloud. They’re colored black or dark brown by the volcanic ash, whereas ones created by wildfires are usually dark gray, due to the smoke and ash.
The speed with which pyrocumulus clouds form and change, combined with the heat of the fire, can lead to quick, massive temperature swings in the atmosphere, producing unpredictable and severe winds.
These can exacerbate the intensity of wildfires, and cause them to move or otherwise behave in unpredictable ways. And that all can put the lives of firefighters and the public at risk.
Sometimes, very rarely, pyromuculus clouds contain enough moisture that they produce heavy rain, potentially helping extinguish the fires that created them. Sadly, that does not appear to be happening this time as California is in the middle of an intense heatwave.