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Forecasts showed 25 mph gusts on the day U.S. Forest Service ignited prescribed burn

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Forecasts showed 25 mph gusts on the day U.S. Forest Service ignited prescribed burn

May 10, 2022 | 6:25 am ET
By Patrick Lohmann
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Forecasts showed 25 mph gusts on the day U.S. Forest Service ignited prescribed burn
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The Hermit’s Peak wildfire started as the Las Dispensas prescribed burn but went out of control. (Public domain photo via the National Wildfire Coordinating Group)

The Santa Fe National Forest team that ignited a prescribed burn last month reviewed forecasts beforehand that predicted wind gusts up to 25 mph and very low humidity, according to National Weather Service records. 

U.S. forestry staff lit the fire anyway and lost control of their burn. It went on to become the Hermits Peak wildfire, which later joined forces with Calf Canyon and is still blazing. The combo fire consumed over 203,000 acres as of Tuesday morning. 

The weather service provides so-called “spot forecasts” upon request for wildland firefighter crews ahead of prescribed burns. In them, they provide detailed weather predictions precisely to help burn bosses determine if conditions are safe for a prescribed burn, considering humidity, wind speed and potential smoke patterns. 

The records do not provide other important information that burn bosses consider, including the level of moisture in the fuel, the landscape features, the personnel available, the plan for the burn and the weather parameters to stay within. The United State Forest Service has so far declined to provide that information  — often compiled into a prescribed burn plan —  to Source New Mexico, saying it would be “premature” due to an ongoing review. 

But the forecasts do shed some light on the decision-making behind starting a fire on a windy spring day in northern New Mexico. Gov. Michelle Lujan Grisham and U.S. Rep. Teresa Leger Fernandez (D-N.M.) criticized the federal agency for the fire, which was supposed to be a 1,200-acre prescribed burn, and called for federal rule changes to prevent them during the windy season. 

The federal Forest Service said “unexpected erratic winds” caused the fire to jump beyond the project boundaries. The agency has also said that forecasted weather conditions were “within parameters of the prescribed burn” but declined to specify what those parameters were.

In three such forecasts requested by forestry officials for each day between April 4 and April 6, the National Weather Service noted high winds and dry conditions. The forecasts on April 4 and April 5 also noted the existence of Red Flag warnings, which are in effect during high wind periods.

The Red Flag warning was no longer in effect in the area of the burn on April 6, the day of the prescribed burn. 

The April 4 forecast, two days before the burn, warned of “critical fire weather conditions” on April 5, due to “strong to severe winds” and falling humidity. The forecast did predict cooler temperatures and less wind by April 6.

On Wednesday, April 6, the day of prescribed burn, the weather service forecasted “very dry and cool today and Thursday. Breezy today, light winds Thursday. Dry and milder Friday and Saturday.” It also said winds would head west at 10 to 15 mph, with gusts up to 25 mph possible, and humidity would be between 9% and 13%.

Other conditions predicted by the weather service were more favorable. For one, the forecasted “ventilation,” the ease at which smoke will be carried up and away from the area, was rated as “excellent.” 

The Forest Service, in a statement Tuesday morning to Source New Mexico, did not address the forecast but said the agency is “committed to conducted prescribed fire under safe conditions” and that a full review that is ongoing will evaluate the conditions, the planning and design of the prescribed burn. 

“The Forest Service will identify and communicate next steps when the report is finalized,” spokesperson Michelle Burnett said. See the Forest Service’s full statement below.   

The Hermits Peak-Calf Canyon wildfire is now the second-biggest in New Mexico history and has destroyed hundreds of structures and caused tens of thousands to flee their homes. 

Cerro Grande fire expert: Feds doing a prescribed burn in spring ‘extremely risky’

Tom Ribe, a local wildland firefighter who wrote the book on the last out-of-control prescribed burn in New Mexico, reviewed the forecasts on Source New Mexico’s request. He said the conditions described in the forecasts should have made the burn boss think twice, especially due to the wind, and what he expects were very dry trees and brush.

“Twenty-five (mph) is a little high. And then given the dryness of the fuels  — if the fuels had been a lot wetter, meaning we’d had a recent snowstorm or rainstorm like a week and a half or two weeks before, then that would have been OK,” he said. “But with fuels that dry, 25’s a little high.”

He also noted that the existence of Red Flag warnings the two days prior to the burn should have been another reason to reconsider. But he stressed that the choices burn bosses face are complex and rely on multiple factors. Sometimes the choice is urgent, based on a fear that a wildfire is imminent that season and that there is no time to wait. 

Burning too early in the spring might mean that the fire doesn’t burn hot enough to kill trees in the understory. Wait too longn and a natural fire could rip through and cause a more devastating fire. All told, Ribe said he respects the difficulty the crew faced. 

“I don’t see anything that says, ‘Absolutely don’t do this (burn). I think just because fuel moistures were so low and the possibility of winds in the future …made it risky,” Ribe said. “But they knew that, and why they did this is unknown.”

Here’s the United States Forest Service’s full statement in response to a Source New Mexico inquiry on the forecasts, from spokesperson Michelle Burnett.

  • The USDA Forest Service is committed to conducting prescribed fire under safe conditions. Our primary goal in engaging in both prescribed fires and fighting wildland fire is ensuring the safety of the communities involved. Our employees are part of these communities across the nation.
  • In rare circumstances, conditions change, and prescribed burns move outside the planned project area and become wildfires. It is imperative that we learn from these experiences. This learning mindset applies directly to the recently escaped Las Dispensas prescribed burn in New Mexico, now named the Hermits Peak Fire.
  • The Forest Service will conduct a comprehensive internal Declared Wildfire Review of the Las Dispensas prescribed fire to understand changing conditions and work towards further mitigating risks in the future.
  • The report will include a review of the conditions on the ground, the planning process and design, an assessment of the decisions leading up to the prescribed fire implementation and a summary of contributing factors.
  • The Forest Service will identify and communicate next steps when the report is finalized.