How climate change is making the fires worse

(The Hill) — Federal officials say climate change is intensifying droughts, leading to far worse wildfires than experts or models have predicted.

This adds to the danger that accompanies one of the US Forest Service’s primary mitigation methods: prescribed burning.

“The fires are beyond our models,” Forest Service Chief Randy Moore said in a statement this week.

Moore said escalating weather conditions were the reason an otherwise routine prescribed burn in New Mexico earlier this year escaped to ignite the largest wildfire in state history.

“Climate change is leading to conditions on the ground that we have never encountered,” he said.

The Forest Service and most of the scientific community consider prescribed burns a key component in protecting western wildfire-dependent landscapes from the most destructive conflagrations.

The agency said in a report that its staff followed a directed burn plan in New Mexico and that burn conditions appeared to be within approved limits to prevent it from escaping.

But persistent drought – which a study published in Nature in February called the worst in 1,200 years – has complicated this picture.

“The first year of the drought is not so bad, the forests still have moisture and energy,” said Marc Castellnou, a fire specialist in the Spanish region of Catalonia, who consults frequently on the fires. in the western United States.

But Castellnou said that after two consecutive years of drought, the forests are more vulnerable.

“They’re just weak and stressed and ready to burn. They cannot respond,” he said.

In a more humid ecosystem, the water evaporating from the landscapes cools them. “But hot weather in a really dry country – there’s nothing to do for evaporation,” Castellnou said. “It just gets hotter and hotter, drier and drier. It’s a feedback loop.

It has been a global problem. In Castellnou’s native Catalonia – a landscape similar in many ways to the American West – it has led to unusually large, fast-moving and aggressive fires.

“It’s May and the fires are already behaving like it’s August or September,” he said. “Models cannot explain what is happening. We knew climate change would have quicker reactions than expected, but even we didn’t expect it. »

Everything Spain faces, he added, is worse for the United States. “We all have big fires too soon,” he said.

In addition to weakening forest ecosystems, the drought has also made the forests themselves more susceptible to burning, fire ecologist Matthew Hurteau of the University of New Mexico told The Hill.

The water in a living — or even dead — tree trunk usually keeps it from catching fire, even in a large fire, he said. “I talk like, lay on the floor, kick and you break a toe,” he said.

Ecologists and fire forecasters rarely paid attention to materials such as dead trees and logs, he said, “because they were simply not available to burn.”

Instead, they focused on smaller fuels found in branches, shrubs, smaller trees and canopies – confident that large trees could char outdoors, but their large size and plentiful content in water meant that they would not burn.

This view has since changed.

“Much more energy stored in large logs and dead trees is available to burn now due to the prolonged drought,” Hurteau said.

Following the huge Creek fire in California, “I went up and saw lines of ash where big logs had been laid – completely burned. Outstanding. I had seen that before, but never on whole hillsides.

This fire started at the site of a 2011-2017 drought that killed and dried out millions of trees – and when it erupted into a wildfire in 2020, the energy stores housed in those trees were able to be released.

This allowed a colossal cloud of pyrocumulonimbus to form, NASA reported – a fire-created storm system that sucks in air, causing it to grow larger and larger in a destructive feedback loop.

The dry conditions mean the fires are behaving disconcertingly, according to the head of the Forest Service.

“This spring in New Mexico, a dangerous log pile that began in January smoldered underground for months, persisting through multiple snowstorms and freezing temperatures, before resurfacing like a wildfire.” , Moore said in his statement. “This type of event was almost unheard of until recently.”

In this environment, burn crews will need to be much more careful, Todd Gartner of the World Resources Institute told The Hill.

“We’re going to have to be more and more conservative in when we use fire, how we use it, and choose the less risky side of the paradigm,” he said. “It’s going to get a little spicier in the years to come, that’s for sure.”

Others pointed out that prescribed burns remain an important tool for forest management and can play a key role in preventing major fires as they help thin forests.

John Bailey, a professor in the College of Forestry at Oregon State University, said when land is not actively managed, plants that fuel wildfires can accumulate.

“Particularly in the West, the fire has been a big part of keeping those fuel levels low,” he told The Hill earlier this month.

“There are a lot of things that we can do in general in our forests…to keep those fuel levels low, and some of it is machine and hand work and some of it is prescribed burning,” a- he added.

Rachel Frazin contributed to it.