Standing at the edge of the charred remains of a wooded area in Weber Canyon on Thursday morning, a fire crew shouts instructions down the line.
“Ready,” shouts Squad Leader Cliffton Fierro.
“Ready,” echoes each crew member, down the line of seven.
“Moving,” Fierro calls out.
“Moving,” the crew responds.
And they begin to walk, slowly working their way through the thick ash that blankets the ground, soft puffs rising with every step. The bright yellows and greens of their uniforms are a stark contrast to the other-worldly landscape they have entered. What just a week ago was a thriving but dry stand of piñon and juniper is now a scorched victim of the Weber Fire, devoid of color with a biting, acidic smell, where the black skeletons of trees stand out against the blue sky.
The crew continues to walk, sifting through the ash with shovel-like tools called “rhinos,” searching for hot spots that indicate the fire isn’t yet dead. From time to time a crew member will kneel down, placing a bare hand near the ground, feeling for heat and signs of life in the ash that remains.
This is the process of cold trailing. One of the last steps in rendering a wildfire powerless, cold trailing allows crews to work around the perimeter of the fire, confirming the fire is completely lifeless.
“This is to ensure the fire’s edge is entirely controlled,” says Tree Escalanti, crew boss for the cold trailing squad out of the Fort Yuma Indian Reservation in California. “We don’t want the fire to reignite or come up behind us. Cold trailing is about safety and control.”
The crews continue to move in a grid-like pattern. As they walk their eyes scrupulously scan the ground, looking for sparks, feeling for heat, and attacking the fire at its source, deep in the ground, in pockets where it can linger for days before roaring back to life, pushed by gusting winds.
A hot spot is located. Three squad members move to the location, digging up the ground and watering down the ash to cool the heat and extinguish the spark. Steam, smoke and ash float into the air as the spot is uncovered.
The ground sizzles as the spray of water hits hot coal and ash, rendering the potential trouble spot impotent. A bare hand is lowered to test the temperature. Only when the squad is certain the heat is gone do they move on, continuing their precise search for more hot spots.
The work is detailed and hands on. Long after the planes and helicopters have done their work, it’s the firefighters on the ground who complete the task.
“This is real firefighting,” Escalanti says, leaning on her pulaski fire tool while she watches her crew work the area. “This has to be done to ensure fires end up controlled.”
Cold trailing efforts focus most often on places where fire can lie dormant for extended periods of time. Tree trunks and roots, dead fall, holes in the ground that soak up ash. These places provide a perfect environment for fire to linger, biding its time before re-emerging as a powerful blaze.
Dry conditions haven’t helped in terms of ensuring the Weber Fire is under control, according to Patrick Doyle, a strike team leader trainee out of Lassen National Park in California.
As of Friday morning, the containment of the fire is at 45 percent.
“The fuel moisture is so low here that the tree roots themselves are holding heat,” says Doyle, sifting through the ash at his feet. “We are not getting the recovery at night that we need. Below the ground, it is still burning.”
The fact that the ground still burns when the flames on the hillside have ceased makes cold trailing a necessary endeavor. And despite living in a world that is more and more technologically dependant, cold trailing is a very simple, and tedious, exercise.
While aerial thermal imaging has been used to map the extent of the Weber Fire, it is the human touch that best identifies when a fire has finally been defeated. Nothing can compare to the precision of bare skin reaching into ash, sensing the degree of heat that remains on the ground.
Of course, bare skin reaching toward ash can also spell disaster if crews are not properly trained, says John Henry, strike team leader, also out of Lassen National Park.
Hands are often the victim of cold trailing.
“The things they have to remember are to use their non-dominate hand and use the back of their hand,” Henry says, demonstrating the best way to test for heat.
“If you burn the palm of your hand, your hand reacts this way,” Henry says, making a quick fist with his left hand. “If that happens, you have a club for the rest of your life. The backs of hands are easier to heal and graft if you get burnt.”
And burns can happen. Both Doyle and Henry mention losing fingerprints on their testing hands, the results of years of cold trailing on wildfires. They have both been fighting fires for more than 20 years.
To outsiders the fire may have seemed all but finished Thursday, with very little smoke rising into the air and no visible flames on the side of Weber Canyon. But Henry says fire is not predictable and cold trailing is necessary to guarantee the fire won’t return.
On Wednesday, a storm ripped through the canyon, whipping winds at speeds upwards of 60 mph and stirring ash across the face of the fire. As a result, Henry says, flames came dancing to life in areas crews thought were finished, highlighting the need for cold trailing efforts around the perimeter of the fire.
“It looks done and people may think it is done,” says Henry, scanning the hillside for signs of smoke and flame. “But it’s not done until we say it’s done.”
In the meantime, crews will continue putting skin to ash on the perimeter of the local blaze, pursuing the moment when they can say with certainty the Weber Fire is no more.
Reach Kimberly Benedict at firstname.lastname@example.org.