Whirlpools of fire, pyro clouds and hazy skies: the extreme behavior of the fire is a glimpse of what is to come.


Given the historic wildfire season of 2020, the rapid return of the destructive flames makes 2021 another potentially record-breaking year for fires.

Man-made climate change plays a role in the worsening of these extreme fires and their likelihood of occurring. Erica Fleishman, director of the Oregon Climate Change Research Institute at Oregon State University, said these extreme scenarios are just a glimpse of what’s to come in the years to come. and the decades to come.

“This is a trend observed and projected for decades by thousands of scientists around the world who have very strong evidence that as greenhouse gas emissions continue, there are more frequent cases of all types of weather extremes, ”Fleishman told CNN. .

The impacts of the western fires have become so significant that the the smoke traveled to the east coast, creating unusually hazy skies and blood orange sunrises. Smoke from the wildfires on Tuesday pushed the air quality score in New York City to be among the worst around the world, overtaking cities like Kolkata in India and Lima in Peru. Other eastern cities like Philadelphia and Washington DC were also shrouded in smoke.
The Bootleg Fire in southern Oregon, currently this year’s largest active wildfire in the country that has so far burned an area larger than Los Angeles, was a major contributor to the smoke which spread across the United States. The Bootleg Fire has intensified to the point that it created your own weather forecast, producing rare and imposing clouds called pyrocumulus clouds.
And it’s not just the American fires that create these clouds of “fire” and smoke spread across the northern hemisphere. Across the border, Canada’s British Columbia declared an emergency on Wednesday due to the rapid spread of wildfires. Nearly 300 active forest fires have been reported in the province. Meanwhile, large swathes of Russian Siberia – where people are used to freezing temperatures – are now on fire with big forest fires, with smoke traveling to Alaska.

Pyrocumulus clouds can penetrate deep into the atmosphere where smoke does not settle, causing it to travel long distances across the country. Some, like the Bootleg Fire, can even penetrate the stratosphere where jets fly. Whereas if the fire is not as strong, it creates a weak updraft where the smoke only impacts the local region.

Fleishman warns that this year’s record-breaking weather events “are unlikely to be an anomaly in the years and decades to come.”

The wind pattern also explains why Washington State and northern Oregon see no wildfire smoke compared to cities across the country. Janice Coen, a scientist at the National Center for Atmospheric Research, examined these weather patterns associated with large fires, noting that downdrafts and hot, dry winds drive the dynamics of the fires.

And as climate change accelerates, these wind regimes will continue to change.

“With climate change, the predicted change is that the jet stream will move north,” Coen told CNN, meaning “we could see less of these events in California and more in Oregon. and in Washington if these wind events, the regional weather pattern, coincide with underlying dry spells during fortuitous ignitions. “

A forest fire can also ignite more fires, creating a feedback loop. When fires burn through fuel-laden wilderness, they release heat that rises and creates a plume of warm water-humidified air in the vegetation. It later forms a cloud and accumulates an electrical charge. Research has shown that positively charged strikes – which occur more frequently in pyrocumulus clouds than in normal clouds – are more likely to start another fire.

Coen also explored a rather dangerous wildfire phenomenon, which is currently taking place in California: fire vortices, also known as “fire tornadoes.”

As the air heated by the fire rises, the cold air rushes to take its place, creating a vortex of fire. It is one of the most dramatic aspects of forest fires, but also one of the most dangerous. According to the Bureau of Land Management, a fire whirlwind is a “rotating vortex column of ascending hot air and gas rising from a fire and carrying smoke, debris and flames into the air.”
Large vortices of fire can have the same intensity as a tornado. the Body Light 2018 outside of Redding, California, for example, spawned a tornado of fire so destructive that it killed eight people and razed several homes. The fatal blaze had winds of over 140 mph, which would equate to an EF-3 tornado, or the third most intense tornado on the EF scale.
“People tend to describe this as a level of fire behavior beyond current models, but that’s because operational models are outdated and decades old,” said Coen, who worked with new models and fire simulations to predict where fire vortices form and develop.

Bill Gabbert, a 33-year former wildland firefighter with the US Forest Service and the National Park Service, describes the event of a forest fire “creating its own time” as perhaps giving people the wrong impression, because it only occurs at a micro-scale. compared to how people generally think about weather events. But this is a fundamental aspect of the behavior of fire.

“It’s all about scale,” Gabbert, now owner of the online news blogs Wildfire Today and Fire Aviation, told CNN. “On a small fire or a fire that is not burning intensely, you wouldn’t notice it. But it becomes much more evident on very large fires exhibiting extreme fire behavior.”

Over the past 20 years, especially the past decade, Gabbert said he and other firefighters have noticed a major change in the way fires have scorched the landscape. Many elite firefighters, fighting an almost impossible battle with the underworld, having left because of the low wages and the physical cost of dealing with raging forest fires.
Heavy smoke and flames on the west side of the Butte Valley Reservoir from the Dixie Fire in Plumas County, Calif., July 21.

“It appears that the higher temperatures and less fuel humidity in the vegetation and the stronger winds have led to more extreme fire behavior that burns faster and more intensely,” Gabbert told CNN. “They’re getting bigger and harder to put out.”

The mix of climatic disasters caused by a months-long drought and pernicious heat waves laid the groundwork for triggering dozens of major wildfires in the West. Philip Higuera, professor of fire ecology at the University of Montana, said that thanks to climate change, record levels of rain and humidity have dried out trees and vegetation, fueling more forest fires.

“You can have the same amount of vegetation in a forest, but if it is wet it is not available for burning,” Higuera told CNN. “Those parts of the west that have record dry fuels, that make more vegetation available to burn – so basically more of the forest is participating in these fires.”

However, the behavior of fire can have many nuances. Coen warns that the mechanisms causing fire to grow are still not widely understood, even in the fire science community.

“Until we have a better understanding of why fires behave the way they do, we need to be more careful about attributing them to climate change,” Coen said. “But it’s important and that doesn’t mean the climate isn’t. It might not impact all fires.”

Yet experts say the amalgamation of historic drought and record-breaking heat waves drying out vegetation are the consequences of climate change. Already, climatologists have discovered that the unprecedented heatwave which engulfed the Pacific Northwest last month “would have been virtually impossible without the influence of man-made climate change.

And as scientists examine how the behavior of this summer’s wildfires can be attributed to man-made climate change, Higuera said it was important for communities to recognize the impacts of a warming world and that people should expect to see more years like 2020 – and now 2021.

“Climate change isn’t the only part of the story,” Higuera said, “but it’s an important part of what allows these widespread fire seasons to happen.”



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