Specialists Seek Answers to Fires in the Ashes

Wildland fire investigators sift through the charred remains of devastation as they search for evidence with profound consequences.

By John Riha
Nov 12, 2023 6:00 PM
(Credit: Austin Sullivan/Getty Image News)


Sign up for our email newsletter for the latest science news

This story was originally published in our Nov/Dec 2023 issue as "Answers in the Ashes" Click here to subscribe to read more stories like this one.

Tom Kluge was at home getting ready for work when he got the call from an emergency command center dispatch. It was Nov. 8, 2018, and a wildland fire had been spotted northeast of Pulga, a remote community tucked away in the northern Sierra Nevada mountains about 35 miles from where Kluge was stationed.

At the time a fire captain specialist and 16-year veteran of a division of the California Department of Forestry and Fire Protection known as Cal Fire, Kluge had multiple responsibilities. He was a law enforcement officer for Cal Fire’s sprawling, 31-million-acre jurisdiction. He was weapons certified and able to make arrests like any state trooper. He was also a qualified wildland fire investigator.

On the day of the call, Kluge’s situational awareness was on high alert. Another nearly rainless summer had left the Sierra Nevada forests desert dry, and the National Weather Service had issued a Red Flag warning for strong winds and low humidity. The fire had started in an area that Kluge knew well; narrow river canyons there made the region prone to high-velocity winds channeled through the rocky corridor.

“When I heard the location, my gut just sank,” says Kluge. “I knew it was going to be a bad fire.” He was right: What followed was the deadliest and most destructive wildland fire in modern California history.

That morning, Kluge was the closest wildland fire investigator to the newly reported blaze. He jumped into his Cal Fire-marked Dodge pickup, and roared out. His fire-resistant Nomex clothes were already stashed in the truck — vital protection he would soon need. As he drove toward the fire, lights flashing and siren wailing, the severity of the burn was already apparent.

“I can see the column of smoke is ice-capping,” he says, “meaning it’s gone above the upper limits of the atmosphere for the day and hitting freezing temperatures and turning white, which is a very dangerous situation.”

He would not know just how dangerous until later that day.

From a single starting point, the Camp Fire would ultimately consume more than 150,000 acres and 18,000 structures — half of them homes. The fire killed at least 85 people. (Credit: NASA/Joshua Stevens)

Finding the source

When a new fire breaks out, wildland fire investigators are among the first to arrive on the scene. Although their work may not be concluded for months or even years, it’s crucial that they begin searching for the fire’s origins and causes before key evidence can be obscured by weather, wildlife, or firefighters moving through the area.

The stakes are high. Their investigations will try to determine whether fires were caused by lightning strikes, human negligence or something more sinister. The results of their work will not only determine who (or what) is responsible, but may also lead to legal proceedings ranging from misdemeanor citations to indictments for arson, criminal negligence and manslaughter. Financial judgments can reach into the millions and even billions of dollars.

Training and testing to become a certified wildland fire inspector — known in the acronym-prone firefighting community as INVF — requires advanced coursework in fire behavior and forensic techniques. Although specific requirements vary from agency to agency, they invariably reflect the investigative procedures found in the Guide to Wildland Fire Origin and Cause Determination, a highly detailed, 337-page publication of the National Wildfire Coordinating Group. Created in 2016 with input from 22 state, federal and international agencies, the peer-reviewed guide is considered the cornerstone of wildland fire investigations.

“It’s really the standard for what we do,” says John Bird, a special operations and enforcement unit investigator for the West Virginia Division of Forestry and a certified wildland fire investigator. “And that’s significant. It lays out systematic methodology and science and if you follow it, it helps your investigation stand up in court.”

Most agencies with wildland firefighting capabilities make sure their personnel receive some basic investigation training. If an engine crew is first to arrive, they’re encouraged to identify the location of the fire before it spreads, take photos or a video if possible, and get contact info from witnesses. That early intel helps qualified investigators zero in on the fire’s general origin area, or GOA.

Gianni Muschetto, Cal Fire’s chief of law enforcement, notes that the agency has between 85 and 100 full-time law enforcement officers who are also certified wildland investigators. But with thousands of wildland fires occurring every year, it isn’t possible to have a certified investigator respond to every fire location. “A lot of fires get investigated by those personnel on the fire engine,” says Muschetto. “That’s why they get that initial training.”

Securing the area and preserving evidence is a primary objective — if not an outright obsession — of investigators. Muschetto says the best way to preserve evidence is to treat all GOAs as crime scenes, keeping the area undisturbed and restricting unauthorized access until investigators know for certain the cause of the fire and whether criminal charges are warranted. “If we don’t secure the scene and take the evidence of a crime, or [if we] mess that up, it could cause us to lose a case and impact a victim’s ability to recover costs later on,” he adds.

(Credit: Matt Dutcher/Moment via Getty Images)

Protection indicators and foliage freeze

To a casual observer, the blackened remains of a wildfire appear as bleak, scorched landscapes, with denuded trees standing over soot-covered soils. But investigators see a tableau of clues: patterns that point toward a GOA.

On smaller burns of a half-acre or so, the GOA may be quickly identified. On larger burns, the GOA may cover several acres. In all instances, investigators begin their search by looking for indicators — residue and charred remains that tell the story of the fire’s passage. These can range in size from large macroscale indicators, such as scorched trees, to microscale indicators that may require a magnifying glass to identify.

Protection indicators are found at both macro- and microscale levels and are considered primary clues: Objects such as rocks, downed logs, and pinecones will show charring on the surfaces exposed to the fire’s advance and unburned surfaces on the protected sides. The charring indicates the direction of the GOA. Taken together, an array of protection indicators becomes a reliable map of the fire’s movement.

“It might be a gopher hole mound, or the stubs of small clumps of grass,” says Muschetto. “You might have to get down and dust off the ash to see what’s left to be able to identify which direction the fire is moving.”

A phenomenon known as foliage freeze is both a macro- and microindicator. It occurs when smaller branches that escape being burned are softened by intense heat. Prevailing winds and drafts created by the fire bend those branches. When they cool, the leaves and needles regain rigidity and remain “frozen” in position — signaling the direction of the fire’s movement.

Burnt grasses provide additional clues. An advancing fire burns away stalks from the top down so only the base of the plant remains. However, a backing fire — one that moves counter to the overall direction of the wind — burns through the bottoms of grass stems, causing the upper stalk to fall and point in the direction of the GOA. A field of burned grasses from a backing fire can be like hundreds of fingers leveling an accusation.

Indicators, however, aren’t slam-dunks. Uneven terrain or a change in wind speed and direction can create contradictory signs. Investigators must continually assess scores of clues to ensure they’re moving toward the GOA and, ultimately, the SOA, or specific origin area, a more precise determination of the fire’s beginning. Throughout the process, they take copious notes and document their findings with photographs — details necessary for writing unimpeachable reports that may be cited in a court of law.

As they begin to zero in, investigators must also slow down. It’s important not to work too quickly and risk overlooking vital clues. Shuffling around on hands and knees is standard procedure as they establish search grids and comb through the ashes, hunting for something that may be no bigger than a single paper match — burnt remains virtually indistinguishable from acres of scorched surroundings.

Cal Fire local police and other organizations, share data to develop a timeline for the fire, which forced the evacuation of several towns, including Paradise. (Credit: Scott Strazant/San Francisco Chronicle/Hearst Newspapers via Getty Images)

Dangerous conditions

Kluge headed up narrow California Highway 70 toward Pulga as the smoke column loomed on the horizon. Nearing the fire, he pulled into a temporary command post that had been set up in the tiny village of Yankee Hill. There he learned that several nearby towns were already under mandatory evacuation. The fire was beginning to rage.

Preliminary reports said that access to the probable origin area was blocked. Kluge put on his protective fire-resistant suit, got back in his truck and headed toward the burn. When he turned onto the road that led into the canyon, he saw the reports were right — falling rocks and burning debris had blocked access. But he had a bit of luck — he’d spotted a bulldozer sitting on a flatbed trailer on a Highway 70 turnout. The heavy equipment operator was responding to the fire alert but didn’t have a specific duty. Kluge gave him one: Clear the access roads.

As he followed the lumbering bulldozer into the canyon, Kluge began to see macro fire patterns — char indicators and foliage freeze. A quarter-mile later, indicators suggested he had entered the backing vector, or “heel,” of the fire. Somewhere nearby was the GOA. The canyon sides were steep and sandy; the sun was hot and the wind was bending the tall conifers. The roar of the growing burn was overlaid with the thrum of air tankers and helicopters as firefighting response began to gear up.

Kluge radioed for additional investigators — it’s strict protocol that wildfire investigators do not work alone on larger burns. The hazards are many: falling debris from fire-weakened trees, smoldering remains suddenly bursting into fresh flames, poisonous snakes. A team watches each other’s backs, especially important in remote locations.

By mid-afternoon, two more Cal Fire investigators arrived, and the team began the painstaking work of mapping the area, planting small colored flags to mark their progress. Red is used for advancing fire indicators, yellow for laterals and blue for where the fire may have backed up. Green indicates points of interest — items that may be specific clues as to how the fire began— while white is reserved for evidence.

The indicators began to lead them up the steep slopes. They zigzagged as they climbed, walking carefully on the incline. “It was slow going,” recalls Kluge. “Two steps up and three steps back.” Above them, shrouded in smoke, was a high-voltage transmission tower. Cresting the ridge, the investigators began to outline a GOA about a quarter-acre in size. Old construction debris was strewn about the footings of the nearly 100-year-old tower: pieces of rusted wire, cracked ceramic insulators, bits of steel. They noted broken equipment up in the tower structure. But as they begin searching for clues, the raging fire threatened their position.

“The winds are intense, the conditions are not great,” recalls Kluge. “We hear the fire roaring. The winds have changed. That’s made it more dangerous. Fuel is starting to pick up with fire intensity. We have fire below us, fire behind us. The only place that doesn’t have fire is the direction we came in from.”

Making the decision to “get the heck off this hill,” the team took photos and made their way out of the canyon. Before leaving, Kluge called a private security service to guard the entry to Camp Creek Road and prevent anyone from entering the origin area.

By evening the blaze had engulfed the towns of Concow, Paradise and Magalia. It moved so fast it had overtaken people trying to escape in their cars. Multiple deaths were a certainty, but an exact count was unknown.

The fire now had a name: the Camp Fire. In keeping with wildfire-incident protocol, it was named after a landmark near the fire’s origin — Camp Creek. The Camp Fire would become one of the nation’s most notorious wildfires, and it was just beginning.

(Credit: Karl Mondon/MediaNews Group/The Mercury News via Getty Images)

Causing a spark

Wildland fires start in a variety of ways and under a host of circumstances, but each incident falls into one of two basic categories. Most naturally caused fires — about 13 percent of the annual total — are the result of lightning strikes. Human activity accounts for the vast majority of the remainder.

Naturally caused fires that aren’t the result of lightning strikes, such as those caused by volcanic eruptions, are extremely rare. A bit more common are fires that start underneath transmission lines because of birds. “You’ll get birds that’ll get electrocuted and fall to the ground on fire,” says Muschetto. “It happens quite often. I’ve had a snake – I’m assuming a hawk took a snake up and landed on the power lines and the snake was big enough it touched between two lines, completed an arc and created a spark. Half the snake was still soldered to the conductor.”

The Guide to Wildland Fire Origin and Cause Determination lists 17 fire-cause categories. Careless negligence is a major contributor: say, throwing a lit cigarette out a car window or burning debris during windy conditions. More obscure causes include overheating electrical cattle fences, tracer bullets fired by gun enthusiasts and sunlight focused through broken glass.

The National Interagency Fire Center (NIFC) says arson may be responsible for as much as 20 percent of all human-caused wildland fires in the U.S. — and in some jurisdictions the number may be as high as 70 percent. Of the 61,429 wildfires attributed to humans in 2022, it’s probable that arsonists set at least 12,000.

Serial arsonists set multiple fires over a span of weeks, months, or even years. They often use time-delay ignition devices so they can put some distance between themselves and the scene of the crime. The average serial arsonist is suspected of setting 35 fires before being apprehended, but due to the difficulty of finding conclusive evidence at every location, is likely to be charged with only two or three.

A suspected case of serial arson begins with the same methodical procedures given to every wildland fire investigation: homing in on a probable cause. If patterns start to emerge — multiple fires occurring in the same general location or the appearance of the same type of ignition device — an arson investigation kicks into gear. A multiperson team is assembled that includes state law enforcement officers and INVFs. Certified wildland fire investigators who are also law enforcement officers, such as Muschetto, make ideal team leaders.

Arson investigation involves tried-and-true detective legwork: interviewing witnesses and poring through security camera footage to look for people and vehicles that regularly appear near wildfire sites. Investigating officers may even don camouflage uniforms and hide in the forests to track the comings and goings of suspects.

If the remains of ignition devices can be found, they’re helpful in establishing a signature for the serial arsonist. For example, some perpetrators attach paper matches to a lit cigarette. The slow-burning cigarette gives the arsonist time to vacate the area and avoid detection before the match heads burst into flame. When discovered, the remains of ignition devices are photographed, carefully extracted and placed in sealed containers. Evidence goes to a crime laboratory where it can be examined for fingerprints and DNA.

Disturbingly, some of the most notorious arsonists have been firefighters and fire investigators. With their intimate knowledge of fire behavior, firefighting responses and investigation techniques, they can be difficult to identify and apprehend.

In one of the most sensational cases, a single fingerprint on an unburned fragment of an incendiary device led to the 1991 arrest of John Orr, a 17-year veteran of the Glendale, California, fire department. Orr, a well-respected fire investigator, was convicted of 20 cases of arson. Authorities believe he may have set 2,000 fires during a seven-year spree, including hundreds of brush fires and a fire that killed four people who were trapped in a hardware store.

(Credit: Karl Mondon/MediaNews Group/The Mercury News via Getty Images)

Root cause

Kluge and his team couldn’t return to the GOA the following day, as howling winds and erratic fire behavior made the location too dangerous. On the third day, Nov. 10, they made their way back into the canyon. There they found a discouraging sight — high winds had dislodged their indicator flags, meaning they had to start all over again to ensure the integrity of their search.

Again, the investigators slogged their way up the steep, sandy slope, methodically planting flags. Near the transmission tower, they reestablished a GOA. They scoured the area with metal detectors and magnets to look for pieces of evidence that might have been covered over. A magnet, for example, might detect the staple holding a recently used book of matches together. The team took hundreds of photos, using telephoto lenses to look closely at the damaged hardware on the transmission tower and confirm the presence of a blackened discoloration that indicated a high-voltage discharge.

As they worked, Kluge had developed several hypotheses, although one was becoming a stronger possibility — that damaged equipment on the tower had arced with enough heat to melt metal, and the molten metal had dripped to the ground, starting fires in the dry grass. Experienced investigators know, however, that any hypothesis must stand up to serious skepticism.

“You never make an assumption,” says Kluge. “You have to go through the scientific process and disprove any hypothesis. It’s absolutely vital that we treat all of our investigations the same way. You have to make sure the truth is told.”

Over the next few days, the investigative team would collect over 200 pieces of evidence from the GOA, each carefully packaged and sent to a guarded storage facility in Butte County. From there, many pieces were sent across the country to the FBI national crime lab in Quantico, Virginia, to be examined by a metallurgist for signs of wear and fatigue. The molten-metal theory was one of several possible explanations. One by one, the investigators analyzed their data to disprove other hypotheses. The nearest railroad tracks were 1,370 feet away, so a random spark wasn’t feasible. Sunrise had occurred after the fire’s start, so light focused through broken glass couldn’t have been a cause.

Slowly, methodically, Kluge’s hypothesis came into focus: A metal C-hook used to secure transmission cables to the tower had, over decades, worn to the point of failure and caused a live conductor to swing down and make contact with the metal tower. The resulting arcing caused molten metal to fall to the ground and start several grassfires. The transmission tower was owned by the massive California utility company Pacific Gas and Electric. In short, it was likely that PG&E was responsible for the destructive Camp Fire.

The Camp Fire caused at least 85 civilian fatalities and injured five firefighters. It covered an area of 153,336 acres and destroyed more than 18,000 structures. In May of 2019, after six months of research and analysis, investigators were able to confirm that equipment failure on PG&E transmission lines did indeed cause the Camp Fire.

“A fire investigation is very, very methodical and it takes a lot of time,” Cal Fire spokesperson Mike Mohler told the Los Angeles Times after the investigative report was released. “Our investigators don’t have an opportunity to be 80 percent right, we have to be 100 percent right, and it’s about getting closure for the fire survivors and victims.”

In December, PG&E announced a $13.5 billion settlement with the victims of the Camp Fire and other transmission-line-sparked California wildfires. In June of 2020, the utility pleaded guilty to 84 counts of involuntary manslaughter.

Risk reduction

Investigators may be devoted to pinning down the causes of wildfires, but they are equally committed to preventing them. Devlin LaFrombois, a certified wildland fire investigator for the Confederated Salish and Kootenai Tribes of the 1.3-million-acre Flathead Reservation in western Montana, says investigation and prevention are closely related.

“Fire investigation and fire prevention go hand in hand,” says LaFrombois. “If we can reduce person-caused fires, that’s our main job. If we can catch arsonists and they get prosecuted, then everybody sees that and hopefully that deters people from lighting fires on purpose.”

He adds that outreach is essential for all firefighting agencies when educating people about preventing wildland fires. Public service announcements on social media, local television and radio help raise awareness of accidental causes of fires, such as burning trash on windy days or neglecting to thoroughly extinguish campfires.

“We go out and visit people,” says LaFrombois. “We have a patrol plan where we patrol in high-fire-danger areas. We get out and talk to the public at recreation sites, campsites, fishing areas. We hand out fire prevention pamphlets at local town events. It’s a fun part of what we do.”

Lucas Woolf, who turned his 23 years as a Forest Service wildland fire investigator into a wildfire investigative business in Arizona, stresses the prevention side of the fire equation: “The No. 1 thing to prevent wildland fires is to know what causes them,” he says. “If you don’t know what’s causing your fires, you don’t know how to prevent them.”

Reflecting on the Camp Fire, Kluge, now a Cal Fire battalion chief, says the incident had a lasting effect on his role as a wildfire investigator. It didn’t alter his meticulous approach to his job, but the devastation underscored the seriousness and profound implications of his work.

“I saw a lot of people who were just shellshocked,” he says, recalling that first day of the fire. “And it hit me hard. These were my partners, people in my community, friends and family that were directly affected by it. It was shocking, disturbing.

“This was more than just a fire investigation. It was humbling. It changed things for me. It put a different perspective on the work we were doing. I was the only person on duty that day, and there was a reason it was me. It was amazing how, by God’s hand or stars aligned or whatever reason, it was me.”

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.