Hermit Peak Blaze Review

The Sangre De Cristo Mountains of New Mexico where the Hermit Peak Fire occurred. Photo George Wuerthner

The Forest Service released a review of the Hermit Peak Fire, which began as a prescribed burn designed to reduce fuels in the Sangre de Cristo Mountains of Northern New Mexico. The Gallinas Watershed Prescribed Fire, Las Dispensas Unit, is located on the Santa Fe National Forest Pecos-Las Vegas Ranger District in New Mexico.

The 341,471-acre Hermit Peak blaze was the biggest fire in recent New Mexico’s history.

The Dispensers area is a mix of ponderosa pine, mixed conifer, aspen, and spruce. The lower elevation ponderosa pine forests historically burned at fairly frequent intervals, but higher elevation spruce and aspen forests tend to have fire rotations in the hundreds of years.

The prescribed burn was ignited on April 6, 2022, but within four hours became an out-of-control wildfire.

The essential thread of the report confirms what some activists and ecologists have been saying about the conditions that create unstoppable wildfires–high winds, low humidity, and drought.

Among other factors, the report highlighted the contribution of extreme fire weather to the spread of wildfire.

Spruce fir forest at higher elevations in the Sangre De Cristo Range naturally have longer fire rotations and have been less influenced by fire suppression. Photo George Wuerthner 

The review also noted, “A thinning project in the burn area opened the canopy in some areas, allowing more sunlight which led to lower fuel moistures. Heavy ground fuels resulting from the construction of fireline for the burn project added to the fuel loading. The surface fuels contributed to higher fire intensities, torching, spotting, and higher resistance-to-control.”

WEATHER AND PRESCRIBED BURN CONDITIONS

The Forest Service team that ignited the prescribed burn was operating under what it believed were prescription conditions. The burn was planned and initiated under current policies and standards.

A post-fire review found that actual weather conditions were significantly drier than assumed. Relative humidity, for instance, was 6%. Low humidity combined with the fact the area had experienced significant drought, less than average winter precipitation, and an abundance of fine fuels created the conditions for an unstoppable blaze.

The week before the burn, snow had fallen. But the influence was reduced by windy, hot, and dry weather. However, on April 6, the weather turned cooler, and the winds abated somewhat.

Contributing factors were the agency’s desire to catch up on a long backlog of prescribed burns, combined with the usual limitations that the agency always faces, like the availability of personnel to monitor the blaze, weather conditions that are in prescription, along with good smoke dispersion.

These factors are one of the reasons why those who promote prescribed burning as a panacea for wildfire reduction are unrealistic. Even under the best of circumstances, the time when all these factors coincide in the same place at the same time is very limited.

This emphasis on getting the job done has put the Forest Service under even greater pressure to perform. The Infrastructure Investment and Jobs Act (IIJA), signed in November 2021, directed $3 billion toward “restoring ecosystems” and reducing wildfire risk. The agency treats about 3 million acres annually for fuel reduction and prescribed fire accounts for 1.4 million acres. The agency is expected to expand to 20 million acres over the next ten years.

WHAT WENT WRONG

Fire crew member with drip torch sets prescribed burn. Photo George Wuerthner

The burn boss and crew were under the impression that they were in “prescription” for setting the fire. And indeed, when they began the ignitions, they were. But to quote John Steinbeck, “even the best-laid plans of mice and men often go astray.”

Several factors contributed to the explosive growth of the Hermit Peak fire. First, while the weather was considered favorable when the burn began, the humidity dropped precipitously during the day so that by 4 PM, the humidity was 10%. Later this was revised to 6%–extremely dry conditions.

Persistent drought, combined with fine fuel (grass, pine needles, and other vegetation with a high surface to volume ratio, usually less than a quarter inch in size—i.e., not trees) accumulations and very dry conditions all conspired to push the burn plan out of prescription.

But the fire weather conditions from Remote Automated Weather Stations (RAWS) in surrounding countries were below the 90^th percentile, which usually indicates safe burning conditions.

Thinning as seen here in Oregon often results in putting more surface fuels on the ground which can sometimes increase fire spread. Photo George Wuerthner

The project area was pre-commercial thinned in 2008, resulting in fuel loading of 20-25 tons per acre, according to the FS. This is a common feature of areas with thinning. Fuel on the ground increases because of mechanical treatment.

As is common practice, a test ignition was slow to spread. However, the area chosen for the test had limited fuel accumulations. Other parts of the burn zone had much heavier fuel loadings. Test ignitions are supposed to be done in the representative of the burn unit, which in this case was not done.

The original prescription plan was not updated to reflect changes in fuel loadings due to fireline preparation and the opening of the canopy from thinning, which led to drier conditions.

Between March 16 and April 3, there was a downward trend in fuel moisture, likely contributing to the transition from surface fire to crown fire. While winds were not excessive, erratic gusts to 15-20 mph caused spot fires (outside of the burn perimeter). These spot fires began to overwhelm control efforts.

To make matters worse, additional firefighter personnel were unavailable because, ironically, they were at the Fire Summit, an annual training session, in Taos, many miles away from the prescribed burn area.

WHAT HAPPENED NEXT

Once the fire had taken off, it grew to 7,500 acres by April 22. Then disaster struck. A separate fire known as the Calf Canyon Fire, which began after another prescribed burn, merged with the ongoing Hermit Peak blaze. Then winds of 60-74 mph fan the flames, leading to extensive spotting. Between April 29 and May 4, the fire grew by 10,000 acres a day! Then a week or even more severe fire weather created unstoppable fire conditions.

It was the beginning of the “monsoon” season with heavy rainfall that finally douse the Hermit Peak Fire, once again making the point that weather, more than other factors, controls large blazes across the West.

TAKE AWAY MESSAGE

The Hermit Peak Fire began as a prescribed burn and eventually burned 341,471 acres, making it the largest wildfire in recent New Mexico history.

There is a role for prescribed burning, mainly to reduce fuels in the immediate area around homes and communities. However, even in such locations, the emphasi should be on hardening the home–reducing the flammability of structures.

Nevertheless, prescribed burning is not effective as a landscape application that many politicians, citizens, and even far too many agency people suggest.

Prescribed burns are always risky because to get an effective blaze, you must ignite the fire when conditions are suitable for fire spread. However, it doesn’t take much of a change in weather to cause the fire to explode, which is what happened with the Hermit Peak blaze.

Even when you are following a fire plan accurately, a drop in humidity or increase in the wind can blow up the fire.

This site was thinned and then burned two years prior to when I photographed the site. Note the abundance of grass regrowth. Photo George Wuerthner 

Another problem with prescribed fires is that you must return again and again to retreat to the site. In the aftermath of a burn, new growth of fine fuels like grass and shrubs is stimulated. Indeed, sometimes you can increase the percentage of fine fuels.

Burning can increase incendiary vegetation like cheatgrass, shifting vegetation towards even greater flammability.

This means you can’t just burn an area once and move on. And this presents a conundrum for fire managers. There is significant pressure to burn more and more acres. But unless you can return to do returns, you may increase the likelihood of a fire.

Why is this a problem? Because what burns in forest fires are the fine fuels. Larger tree boles don’t burn well. That is why you get snags.

Thinning or logging is often done before a prescribed burn, but this has significant consequences for wildfire spread. As noted in the Hermit Peak review, pre-commercial thinning and fuel piling before the burn put more wood on the ground. And logging opened the canopy, which intensified the fuel drying and enabled greater wind penetration.

The research shows that the best way to reduce fuels is to thin, followed by at least two prescribed burns. But this is seldom done.

This chart shows how climate influences fire spread and ignitions. Early in the 1900s as much as 50 million acres burned. Then mid century from 1940s to 1980s, the climate was cool and moist, far fewer acres burned. Nature was good at suppressing fires. Then after 1980s with climate warming, fire acreage again soared. 

Finally, the idea of “fuel buildup” from a “hundred years of fire suppression” is a great exaggeration. It doesn’t apply to most western vegetation, which naturally had long fire rotations, often hundreds of years between fires, like lodgepole pine, spruce, fir, sagebrush, juniper, and other vegetation types. Moreover, the idea that before suppression efforts, all plant communities experienced frequent, low severity blazes set by native people is simply false.

Secondarily, fire suppression effectiveness was questionable until after WW11, when bulldozers, helicopters, planes, and other modern equipment were initiated.

Lastly, the climate was and continues to be the dominant factor influencing ignitions and fire spread. During the middle of the last century, when many suggest fire suppression was “successful,” the climate was considerably more relaxed and moister. Then in the late 1980s, human-caused climate warming began to kick in and create the ideal conditions for massive wildfires.