From the Cliff High Volume Weather Blog
On April 6, a wildfire was accidentally ignited by a regulated U.S. Forest Service employee near Hermit’s Peak, New Mexico.
Regulated burning is intentional burning intended to reduce the risk of catastrophic wildfires by igniting surface fuels under conditions that are unlikely to cause uncontrolled wildfires.
This Hermit’s Peak blaze began about 30 miles east of Santa Fe and 15 miles northwest of Las Vegas, NM. Along with another escape fire two weeks later (the Canyon Fire), the Hermit’s Peak fire has now burned 342,000 acres and destroyed more than 900 structures.
Hermit’s Peak / Calf Canyon Flame Area as of June 27
Expenses for fire fighting are now over 250 million dollars and the total damage, all the responsibility of the Federal government, would easily run into the billions of dollars.
Satellite image of the fire area last week.
Red indicates burned area and bright orange indicates active fire.
As I will describe below, none of this has to happen.
Inadequate use of meteorological data and forecasts, neglect of the large amount of flammable surface fuels available, and poor decision-making all contributed to this disaster. Climate change is Not a major contributor to this wildfire, contrary to suggestions by certain media (e.g. Washington Post, Seattle Times) and some Forest Service officials.
Last week, the Department of Forestry released an official report about the incident. While acknowledging some shortcomings (such as the inability to extinguish fires on site if burns are prescribed), the report provides an incomplete description of the conditions leading to the fire and does not note the failure to take advantage of the fire. modern meteorology. prediction tools. It also erroneously suggests a major contributor to climate change.
This blog will tell the actual story.
Dangerous accumulation of flammable fuels prior to combustion
Before the fire, the accumulated amount of surface fuel (e.g. grass) has gone beyond normal and very dangerous. This was recorded on one of the websites of the Forest Service (Fuel.net) and a specific warning on the hazards BEFORE the fire was given by a leading expert in surface fuels for the Forest Service, Dr. Matt Reeves.
Greater than normal rainfall last summer during the Southwest Monsoon resulted in abundant grass growth, which dried up during winter and spring under the influence of a mild La Nina (which caused the southwestern United States to dry period in the cool season). Neither of these conditions is related to global warming.
Dr. Reeves (on March 1) notes that the surface fuel density east of New Mexico is above normal (yellow and green in the image below), representing a significant wildfire threat. The location of the Hermit’s Peak flame is indicated by a black arrow.
A strong wind / drying on the day before the fire
On the day before the fire, there was a fierce dry event, with very strong desiccant winds, low humidity, blowing through the area. This is illustrated by the Heat-Dry-Wind index that combines wind speed and the ability to dry the atmosphere (values shown below are for the area around the fire).
The BIG spike in drying conditions happened on April 5th. Think of it as a dry storm quickly absorb moisture from dead grass and other vegetation.
This severe dryness was evident in a nearby area of the United States INGREDIENT weather station (Pecos, NM), where gusts of up to 40-50 mph and relative humidity dropped below 20% on April 5. Any grass or light fuel is completely dry after ” drying storm”.
Ominous weather forecast ignored for April 6
Now we’ve come to the day of the prescribed bushfires and runaways.
According to the official Forest Service report, there is no specific meteorological support for burns and only some guidance. spot forecast requested from forecasters of the National Weather Service in Albuquerque.
The Forest Service report states that the main reason the fire escaped Forest Service officers was “the wind of change and change”. That’s the truth such winds were clearly forecast before the prescribed burning started during the late morning of April 6.
Consider the National Weather Service’s HRRR forecast model in action, run at high resolution across the entire US hourly, providing timely and accurate high-resolution weather predictions . These predictions were available to the people of the Forest Service prior to the fire.
Below is the HRRR forecast for surface gusts. Running this predictive model begins at midnight Mountain Daylight Time (MDT) and will be available on the web by 2:00 a.m. on April 6 (before the Forest Service starts the fires). The graphs below show the forecast wind direction and wind speed (drawn by UW research meteorologist Jeff Baars).
At 6 a.m. MDT, gusts are predicted from near and east of the Hermit Peak, reaching 15-20 knots. Winds are variable near the crest with strong westerly westerly winds.
By 11 a.m., winds were already strong to the east of the Hermitian Peak, and a strong northwesterly wind was beginning to push through the terrain just west of the Hermitage. A large wind change and strong winds are imminent. This is when they decided to light more fires.
By 3 p.m., as the prescribed fires begin to spiral out of control, northwesterly winds are predicted to hit the Hermitian Peak regions, with gusts of up to 20-25 mph. As shown by observations at Pecos RAWS (shown above) and other local observations, this is a good forecast.
To further illustrate the realism of the forecasts, below are the peak gusts on April 6. 26 mph in Pecos and 31 mph in Las Vegas, NM.
Maximum winds (mph) on April 6 in the fire area.
Substantial wind variability is also forecast by the National Weather Service National Blend of Models (NBM). Below is the forecast for Las Vegas, NM airport, given at 1 a.m. BEFORE DAY (times are in UTC/GMT).
Wind gusts (GST) were predicted as high as 24 knots that afternoon. And wind direction (WDR) is forecast to shift from south (17.18) in the morning to north and then northerly (3.5 to 34.33) in the afternoon.
The bottom line is that increasing winds and wind shifts were clearly predicted by the National Weather Service’s HRRR model and the NWS NBM system. well before they happenand subsequent projections enhanced the threat further.
Therefore, strong, gusty winds with a change of direction will NOT surprise Forest Service officers.
But it’s even worse: the air predicted to pass through the terrain west of the Hermit Peak is much drier and therefore more prone to burning.
The relative humidity graph observed at the nearby Pecos RAWS site (repeated below, Show Local Standard Time), shows this deep aridity, with relative humidity dropping to BELOW 8% in the afternoon of the 6th.
The weather model forecast a day earlier clearly showed very dry air pouring over the terrain from the west. Below is a high resolution relative humidity forecast (starting at 6pm BEFORE DAY) for relative humidity.
The 6am forecast shows moderate relative humidity (50-60%) around the Hermitian Peak.
At noon, more drier air was (correctly) forecast to move in, with values less than 25% at the top of the Hermit and much drier air just upstream.
And by 6pm, the values had dropped to 10% and below.
Putting it all together
So, on the morning of April 6, the forest ranger decided to burn according to regulations:
1. With much higher surface fuel load than normal.
2. The day after a severe dry event is taking place.
3. When the National Weather Service’s operational forecasting guidelines forecast a change in high winds and strong winds during firefighting operations.
4. When the National Weather Service, which guides the forecast operation, predicts a sharp drop in relative humidity during the fire period.
Furthermore, Forest Service staff did so without dedicated meteorological guidance and without assurance that there were sufficient firefighting resources to deal with the out-of-control fire.
These actions are irresponsible and do not reflect the high standards expected by the USDA Forest Service.
These actions have not only resulted in billions of dollars in damage, disrupted lives of thousands of New Mexico residents, and lost valuable natural and historic resources, but also undermined this vital mission. It is important to responsibly restore the dangerous, fire-prone western forests, damaged by decades of fire suppression and mismanagement.
Finally, there needs to be a special place in Hades for those in the media and government to blame poor forest management and regulatory blunders on climate change, as illustrated by the article. newspaper and headline below in the Seattle Times. Such misinformation/misinformation undermines our ability to repair western forests and puts people and the natural environment at risk.
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