Winds of Change

LANL scientists are developing wildfire tools for the new climate

As wildland fires across New Mexico erupted in April—growing in size and scope as intensive winds rattled the state—Los Alamos National Laboratory research scientist Adam Atchley’s pervading thought was and continues to be: “We are watching climate change unfold. And we’re seeing it happen in fire behavior.”

Atchley is part of a team of scientists creating tools designed to meet that unfolding reality. Specifically, they are creating modeling programs that will allow for safer prescribed burns.

Before the early and dramatic start to the state’s wildfire season had begun, Atchley had been scheduled to deliver talks on wildfire, water and climate change as part of LANL’s Frontiers in Science lecture series this week. Those talks were postponed due to the Cerro Pelado fire, which began April 22 and had grown to 43,000 acres as of press time.

The cause of the Cerro Pelado Fire remains unknown. But the Hermits Peak/Calf Canyon Fire, which had grown to more than 200,000 acres as of press time, began in part as a prescribed fire (as, of course, did the Cerro Grande wildfire in 2000, which ultimately burned 43,000 acres and caused approximately $1 billion in damage).

Initially, the 1,207-acre Las Dispensas prescribed burn was designed as part of a larger project to protect the Gallinas Watershed, one of the City of Las Vegas’ primary water sources. Instead, by April 6, it had become the Hermits Peak Fire and, after extreme weather on April 22, merged with the Calf Canyon Fire.

The early start to the state’s wildfire season, coupled with weather conditions characterized as “historic,” put the kibosh on prescribed burns in the immediate future.

Carson National Forest fire managers had initially announced plans in early April for five prescribed burns totaling more than 8,000 acres throughout May, all of which are now postponed indefinitely, according to CNF Public Affairs Officer Zach Behrens. Santa Fe National Forest has also since canceled indefinitely a prescribed burn that had been scheduled last month for more than 1,000 acres in the Santa Fe Watershed.

Gov. Michelle Lujan Grisham, speaking on April 24, acknowledged the importance of prescribed burns but said she had been “barking” at federal officials to avoid having them during New Mexico’s windy season. State Forester Laura McCarthy followed the governor’s comments by noting “there probably won’t be any more prescribed burning in the spring,” adding that forest managers would look to the fall when “we may have a burn window right after the monsoon.”

US Rep. Teresa Leger Fernández, D-NM, last week wrote to US Forest Service Chief Randy Moore describing herself as “shocked” the forest service would perform a prescribed burn given the dry and windy conditions present during the Las Dispensas burn and requesting an investigation regarding the decision.

But finding the right window for prescribed burns is tricky in the face of climate change, Atchley says, and the reason why new models are needed to conduct them successfully.

First, though, he offers a précis of why they’re needed:

“I think the thing that we all have to remember, and sometimes repeat to ourselves, is that the forests we live in are in fire-dependent ecosystems. And so, without fire, you really don’t have the ecosystem.”

Our forests without fires, he says, would be akin to rainforests without rain, aka, no longer rainforests. Prescribed burns, he says, provide the opportunity to control the fire’s impact, versus wildland fires, which have the capacity to burn so severely as to create what’s known as an ecosystem transition, in which the landscape is so torched it has a reverberating impact on all aspects of the ecosystem—its water and wildlife. And that ecosystem transition results in less carbon storage, which, of course, is what’s causing climate change in the first place.

The challenge, however, is existing fire models don’t work for the current conditions.

“We built these past models based on what we call empirical data. And that’s basically observations that we’ve made in the past,” Atchley says. “Because of climate change, we’re now outside of a calibration or validation range of the models and sometimes that means that the models aren’t able to predict what’s going to happen when you have something like these wildfires.” Additionally, “the ecosystems themselves have changed because of climate change [and] also past fire suppression. So, these ecosystems are changing, and we’re not seeing the same type of fire behavior.”

The factors go beyond wind, he says.

“We consider wind, but we also consider fuel moisture,” he says. “And that’s probably one of the biggest drivers of fire behavior. We’re dealing with a double whammy here where we’re in a 20-year drought, a mega-drought.”

New Mexico’s topography also plays a role: “At a certain elevation, a prescribed fire might be OK. But at lower elevations where it’s drier, and the snowpack has dropped off a little earlier, it’s not OK. And those types of complications make it really hard to conduct prescribed fire. So, our hope— our goal—is that the science we provide will help prevent things like the Hermit Peak/Calf Canyon Fire.”

The new tools include what LANL describes as a “suite of computer models.” One of those, HIGRAD/FIRETEC, uses physics principles to produce 3-D simulations. That model, however, comes at a computational price, Atchley says, meaning it’s too expensive and too slow to be used in an operational way. For that the lab has what’s known as QUIC-Fire models (Quick Urban & Industrial Complex), which use machine learning and, Atchley says “runs 100 times faster and can be run faster than real time on a single processor.”

A hydrologist by training with a background in plant and forest ecology, Atchley’s particular interest is looking at issues such as how plant community structure and forest structure influence hydrology and fuel moisture. He’s been working on a model “that simulates ecosystem response to simulated fire behavior,” using the new modeling tools.

The bottom line? “In our landscape, fire is a good thing. In our landscape, we have to live with fire. And it’s not always a bad thing. In order for it to be a good thing, we need to be able to perform prescribed fire. And there’s a whole science about it that we’re working on…so that we have the benefits of fire on the landscape rather than the problems of fire on the landscape.”

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