Why did the Forest Service Start a Big Forest Fire in New Mexico?
The recriminations have begun. The 320,000-acre Hermit Peak Fire in northern New Mexico has burned more than a thousand structures, some of them homes. It is the largest fire in recent New Mexico history. People are understandably angry, and it turns out they have someone to blame. They can blame the US Forest Service which has admitted it unintentionally started two separate prescribed fires that blew out of control in extraordinary winds on April sixth.
Usually, forest fires are started by lightning, or campfires abandoned, or smokers, or fireworks or by burning cars, or gunshots or little boys playing with matches, or church picnics. Investigators can track those perpetrators down and fine them. In this case we have whole agency and specific personnel, and we have a long history of distrust of the Forest Service in rural New Mexico.
This time it was the US Forest Service which had plans to burn 20,000 acres of land near Las Vegas in the next few years to restore fire to a fire starved landscape. They had thinned tree thickets over hundreds of acres and piled the slash. They burned these piles in the dead of winter in February when it was snowy on the ground. Yet defying odds, embers from those pile burns lit the Calf Canyon Fire in April, two months later. This is highly unusual to have heat persist over such a long time through snowstorms and freezing nights and many weeks.
They also burned 1200 acres of land with strategic ignitions and fire lines in place all around the area. The Las Dispensas Prescribed Fire was meant to clean up dead logs, sticks, pine needles, and small trees. Everything went fine until strong winds blew embers across their containment lines and fire took hold in the above listed fuels outside of their lines. Off to the races the fire went, burning 30,000 acres in one day. (The Las Conchas Fire in the Jemez Mountains, started by a tree striking a powerline in 2011, burned 45,000 acres in one day.)
Both recent burns were lit to eliminate burnable material and open the ground for new plant life. They were lit to chip away at a huge backlog of acres of public land that are exceptionally flammable because native fire, started by lighting, hasn’t been able to visit these areas for a century when such fire would have come by every two decades before modern people interfered with the natural fire cycle.
The Forest Service was doing the right thing in principle to ignite these fires. Not only were they reducing fuel to feed future wildfires, but they were also restoring the forest’s health in various ways. Science vindicates the activity. Science drives the activity. But good sense did not drive the timing of the Las Dispensas prescribed fire.
The winter pile burning was a low-risk operation, and it allowed the Forest Service to burn a large amount of fuel in a short time without harming the forest substantially. Hundreds of thousands of acres are burned in this way all over the West with few mishaps. The National Park Service burned hundreds of acres last winter in the Valles Caldera National Preserve about 50 miles to the west with no problems.
The US Forest Service has been managing large areas of forests and grassland in New Mexico since around 1900. During most of that time, the agency believed that fire was a bad thing that must be extinguished. Not until the 1970s did this reaction start to subside on a national level. The National Park Service in the southern Sierra Nevada had begun to implement prescribed fires following research from scientists at the University of California, Berkeley. Gradually the wisdom of reintroducing fire to forests where it had been native for thousands of years took hold in the national park system. But it was difficult to overcome the traditions, biases, and inertia at the US Forest Service.
By the 1990s the US Forest Service was starting to implement prescribed burns. Their fire fighters learned a whole new skill set in the process and they became better firefighters on their fire suppression operations.
Planning
Before burning an area, federal agencies go through a planning process starting with research the geography and the living and dead vegetation in the area they plan to burn. They measure the moisture in the dead material on the ground because the dryness of pine needles and dead logs will affect the way the fire burns. They look at the lay of the land and how the dead and living vegetation is spread out on the topography. Topography has a huge effect on how fire behaves. They look at weather and set limits on when the fire can be lit based on wind speed and direction, moisture in the air, and how the smoke will behave (called ventilation).
These days they feed this information into a computer program that digests the data and establishes the safe limits for firing operations. It used to be that experienced fire managers would consider the weather and fuels and make decisions based on their experience. This may also still happen, but the computer models are important now. In fact, computer models predict fire behavior on large wildfire events also and help firefighters lay out fire lines, bring in people, and target fire with airplanes and helecopters.
The Santa Fe National Forest developed a planning document in 2018 that laid out the conditions and personnel requirements for their plans to treat 20,000 acres with fire over the following years in the area west of Las Vegas, New Mexico. The Calf Canyon Pile Burn and the Las Dispensas Prescribed Fire were part of the Gallinas Watershed RX plan as it was called. This plan was the paper driver for the prescribed fire that left its control lines and ultimately burned a large area east of the Sangre de Cristo Mountains and inside that mountain range.
For example, we can learn that the La Dispensas prescribed fire was planned to have a total of 18 people overseeing the ignition of 1200 acres of mountain country. The fire was to be lit with winds below 15 mph and the burn boss could call for additional people to help if needed. Also, rather than burn with firefighters carrying drip torches to light the ground on fire, they could use a helicopter that dropped incendiary balls from the sky, greatly speeding up ignition and saving the energy of the fire workers on site. I don’t know if they used the helicopter or not.
Thirteen different burn projects were covered by the Gallinas Canyon RX plan. Since the plan was released in 2018, I don’t know how many of these units were burned before this spring. The Calf Canyon and Las Dispensas were dispatched this spring and looking at the list of burn units I suspect that most of the others were burned in the wildfire that resulted from the escape of the prescribed fires.
The person in charge of the prescribed fire is called the “burn boss.” Simple enough. This person bears decision responsibility for the burn and its aftermath. It is an incredibly responsible position, because of the possibility of escape, of burning someone’s private property, of injuring a fellow firefighter, or committing some other mistake that brings criticism down upon you or has serious safety consequences.
From my somewhat limited experience in the wildland fire world, I saw that finding people willing to be burn bosses for prescribed fire grew more difficult over time because of the Cerro Grande Fire disaster, the Outlet fire (north rim) and others. This prescribed fire escape will make that job even harder to fill in the future unless some immunity is granted legislatively or administratively to burn bosses in complex burn situations.
Climate and Prescribed Fire
As the climate warms, moisture evaporates from the landscape faster. Snow melts from the high country faster in the spring and runs through watersheds more quickly than it did before climate warming. Moisture laid into forests by winter snows evaporates more quickly in the spring. Prescribed burning relies on moisture to moderate fire behavior. Yet with global warming, the windows of opportunity for burning in moist conditions are closing faster. Agencies seeking to treat large areas of fire suppressed forests find fewer opportunities.
The Las Dispensas/Hermit Peak mishap reveals this problem starkly. Clearly the Forest Service should have waited until fall, after summer rains to ignite the broadcast burn. We’ve learned before that spring burning in the southern Rockies is too risky with fuels so dry and increasing wind as the years go by.
Larger weather patterns driven by El Nino and La Nina Ocean temperatures will continue to change as climate change tightens its grip on our future. The position of the jet stream is changing over time as well and these big picture factors will probably make opportunities for prescribed burning and letting lightning fires burn fewer over time.
To me this means we need to increase size of prescribed burns as time goes by. We need to be burning 5000 acres instead of 1200 acres at a shot. And we need to lift the current moratorium on prescribed fire as soon as possible, especially in the wetter parts of the country.
Inevitability
People are upset that the Hermit Peak fire was started by controlled burns. In fact, this fire was inevitable. It was just a matter of time. The fuels that burned needed to burn and while the dryness we have today made them burn hotter than they would have in moister times, they needed to burn, especially in places like the Pecos Wilderness Area where incredible piles of dead trees from blowdowns and sick young trees show how long natural fire has been suppressed in these forests. Overstocked forests are more susceptible to disease and diseases like bark beetle are rampant in southern Colorado and northern New Mexico.
The next big fire will be started by lightning or a member of the public. This will happen. We don’t know when but large fires in northern New Mexico are a 100% certainty. This time we have someone to blame who can pay the bills for private property losses. Next time we won’t.
Tom Ribe
