From The Durango Herald (Jonathan Romeo). Click through for the photos:
‘Pyrocumulous’ cloud collapses at wildfire, sending ash and smoke toward Durango
No, the skies above Southwest Colorado on Wednesday aren’t a sign of a coming armageddon, though given everything that’s happened in 2020, perhaps it wouldn’t be all that surprising.
Instead, the strange light over the region is the result of a unique and rare weather phenomenon set off after a series of events associated with the Pine Gulch Fire burning north of Grand Junction.
Erin Walter, a meteorologist with the National Weather Service in Grand Junction, said a storm in northeast Utah late Tuesday night brought a burst of cold air and strong wind crashing into the Pine Gulch Fire.
That collision caused what’s known as a “pyrocumulous” cloud, basically a thunderstorm driven by smoke and hot fumes from a fire, to collapse.
“When that storm collapsed, it pushed a lot of hot and dry air down into the Grand Valley, along with a lot of debris and smoke,” Walter said.
As a result, temperatures in Grand Junction spiked around midnight from 78 degrees to 90 degrees within just a few minutes, Walter said.
As ash and soot continued to fall, winds started to bring the plume south, hitting Durango with smoke and haze by late morning.
“That’s really why today has been so different and drastic,” Walter said.