With more than 600 square miles burned so far, the Park Fire is already one of California’s biggest wildfires ever — and it’s still far from contained . Driven by strong winds, the blaze has chewed through desiccated plants, spewing smoke high into the atmosphere. So much smoke and rising hot air, in fact, that it’s been creating fire tornados and one of the strangest natural phenomena on earth: the pyrocumulonimbus cloud, or pyroCb.
It’s a smoke thundercloud that makes a dangerous wildfire like the Park Fire, burning in the northern part of the state, even more unpredictable. PyroCbs can produce lightning that goes on to spark more fires around the very blaze that made the clouds. And as the planet warms, pyroCbs seem to be growing more common, since they’re spawned by the biggest, fiercest wildfires, which themselves are getting worse. “PyroCbs are such massive, almost volcanic-like eruptions,” said Rajan Chakrabarty, an aerosol scientist who studies the clouds at Washington University in St. Louis. “These pyroCbs create their own fire weather.”