LANGLEY, Va., Oct. 20 (UPI) -- Massive pyrocumulonimbus storms, mixing smoke and fire with features of a violent thunderstorm, create huge amounts of atmospheric pollution, scientists say.
Cumulonimbus clouds -- massive, anvil-shaped towers of power reaching 5 miles high and hurling thunderbolts, wind and rain -- are imposing enough, researchers say.
Add smoke and fire and you have pyrocumulonimbus, an explosive storm cloud actually created by the smoke and heat from fire that can ravage tens of thousands of acres, a NASA release says.
And so-called pyroCb storms funnel smoke from fires into the Earth's atmosphere in a "chimney" effect, trapping large volumes of pollutants in the upper atmosphere, researchers say.
"An individual pyroCb can inject particles into the lower stratosphere as high as 10 miles," Glenn K. Yue, a NASA atmospheric scientist, says.
Scientists had long believed nothing less energetic than a volcanic eruption could penetrate Earth's "tropopause," the barrier between the lower atmosphere and stratosphere, Yue says.
But Yue says his research shows pyroCb storms pack enough energy, and that they happen often.
"Our paper … shows that pyroCbs happen more often than people realize," Yue says.
In 2002, he says, various sensing instruments detected 17 distinct pyrocumulonimbus events in North America alone.