John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
This stunning cloud was caused by updrafts from wildfires.
With their tornadoes, hurricanes, and hailstorms, America's East and Midwest hog a lot of the eye-popping weather phenomena. But the West just proved it can generate spectacular airborne sights, too, with a flame-fed pyrocumulus cloud billowing over the land like a Cold War nuclear test.
The drought that's squeezing the life out of the West—seriously, people have taken to painting their lawns green rather than waste water—has created the perfect conditions for wildfires. And with the sparking help of lightning, blazes are popping up all over the place. The outbreaks are so ferocious that California Governor Jerry Brown declared a state of emergency this weekend, as towns evacuated, several homes got incinerated, and more than 100,000 acres of vegetation were reduced to embers in the northern part of the state.
The staggering energy these fires produce is clear in these wild photos shared yesterday by NASA and taken on July 31 by James Haseltine of the Oregon Air National Guard, which is helping fight the flames. The images reveal the development of a major pyrocumulus above the Oregon Gulch Fire, part of the larger, ongoing Beaver Complex fire spanning the border of California. NASA explains more about this unusual weather:
Pyrocumulus clouds—sometimes called "fire clouds"—are tall, cauliflower-shaped, and appear as opaque white patches hovering over darker smoke in satellite imagery. Pyrocumulus clouds are similar to cumulus clouds, but the heat that forces the air to rise (which leads to cooling and condensation of water vapor) comes from fire instead of sun-warmed ground. Under certain circumstances, pyrocumulus clouds can produce full-fledged thunderstorms, making them pyrocumulonimbus clouds.
Here's another view from Haseltine:
What people are seeing on the ground is almost as striking. These photos were taken near the town of Burney in northeast California:
NASA's Aqua satellite also captured a rare image of a fully developed pyrocumulus wafting off the Beaver Complex. This shot from Saturday shows the wildfire sending huge amounts of dirty smoke into the atmosphere, where it would later spread from Oregon all the way over Montana: