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Scientists study ‘pyrocumulonimbus’ clouds fueling Australia wildfires

by Kiet Do, KPIX-TV (San Francisco) |

SAN JOSE, Calif. – Bay Area climate scientists are keeping a close eye on an a never-before-seen phenomenon fueling the wildfires burning in Australia.

Since last September, uncontrolled wildfires have encompassed much of Australia in flames, smoke, and devastation and turned the once-rare weather phenomenon of “pyrocumulonimbus” cloud into a regular occurrence.

Smoke plumes from a typical wildfire rise into the atmosphere, only to be capped off by upper level winds.

“A pyrocumulonimbus is a fire-generated thunderstorm, and it’s when a fire gets so big, and there’s so much heat release, that the air mass from the fire actually rises vertically into the atmosphere, but really, really deep,” said Craig Clements, founder of the Fire Weather Research Lab at San Jose State University.

The result is a massive, unpredictable column of smoke and heat that punches through the atmosphere, creating its own extreme weather of lightning, downdrafts and fire tornadoes made of flames.

The lightning and swirling gusts can send embers flying long distances, sparking spot fires miles away from the fire line.

The pyrocumulonimbus clouds have been seen on rare occasions in California and other western states, but the fires in Australia have seen historic, unprecedented activity that will provide fire researchers like Clements with valuable data to study.

“To have so many at one time, is unique. This is probably the largest outbreak of pyrocumulonimbus on Earth,” Clements said.

The fires span an area the size of California, Oregon, Washington, and Montana, and have killed 24 people and burned 2,000 homes. But Australia hasn’t yet hit its peak of summer fire season.

“I think we’ve probably reached a tipping point globally. There’s a manifestation of climate change in Australia,” said Dr. Alison Bridges at the SJSU Meteorology Department, and former chair.

Bridges says months of data analysis must be performed before Australia’s fires can be definitively linked to climate change, but the early indications are strong.