Rare weather phenomenon casts strange light over Southwest Colorado

‘Pyrocumulus’ cloud collapses at wildfire, sending ash and smoke toward Durango
Durango photographer Dan Bender set out early Wednesday to capture pictures of the sunrise on Molas Pass. “There was more smoke in the sky than I have ever seen on the pass, which is about 11,000 feet,” he said. “... (But) there was a silver lining. When the sun came up, it created beautiful shades of red and orange.”

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 “pyrocumulus” 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.

Durango photographer Dan Bender set out early Wednesday to capture pictures of the sunrise on Molas Pass.

Durango photographer and retired La Plata County Sheriff’s Office spokesman Dan Bender said he set out early Wednesday to capture the sunrise on Molas Pass. When he stepped out of his car about 4:30 a.m. at the top of the pass, he could not see his hand in front of his face, he said.

“If you have ever been inside a cave when they turn the lights out, it was that dark this morning,” he wrote in an email to The Durango Herald. “I could not even see a horizon for reference. I am glad I had a flashlight with me.”

Bender said he assumed smoke from regional wildfires would settle overnight in the valleys, creating interesting photographs from the pass. “I was grossly mistaken,” he said. “(But) there was a silver lining. When the sun came up, it created beautiful shades of red and orange.”

Walter said the whole series of events that happened Tuesday night are not a common occurrence.

“It’s a unique event,” she said. “It was fascinating to see.”

The next few days don’t appear to offer any relief from smoke or haze. Walter said there should be an uptick in thunderstorm activity, but little chance of rain.

Four large wildfires are burning in Colorado, leading Gov. Jared Polis to enact a 30-day statewide fire ban. As of Wednesday, the Pine Gulch Fire had consumed more than 125,000 acres.

The San Juan National Forest also announced Stage 1 fire restrictions on all forest lands, effective Thursday.

San Juan Basin Public Health said La Plata County is under an air quality health advisory until 9 a.m. Friday.

The health department says if smoke is thick or becomes thick residents may want to remain indoors, especially those with heart disease, respiratory illnesses, the very young and the elderly.

SJBPH also recommends considering limiting outdoor activity when moderate to heavy smoke is present and relocating temporarily if smoke is present indoors and is making you ill.

For more information: https://www.colorado.gov/airquality/addendum.aspx#smoke

jromeo@durangoherald.com



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