Author(s): Rick Trembath. Published on September 1, 2011.


(Photograph: Corbis)

Life in the Interface
Big wildfires frequently present organizational and tactical challenges for the fire service. It’s in the wildland-urban interface, though, where things get really complicated. 

NFPA Journal®,  October 2011

By Rick Trembath 

On the afternoon of June 13, I arrived at the 3,500-acre (1,416-hectare) Monument Fire near Sierra Vista, Arizona, a community of 43,000 located about 60 miles (97 kilometers) southeast of Tucson. The fire was located above Ash Canyon in the rugged Huachuca Mountains. Looking at it with my binoculars shortly after I arrived, it didn’t look like it was going away anytime soon. Our team wouldn’t have been deployed on this fire if it didn’t have significant potential to expand and threaten structures.

I live in northwestern Montana, and I’m part of a 56-member Type 1 Incident Management Team (IMT1). There are 16 Type 1 IMTs in the U.S., complete teams that can either augment ongoing wildland firefighting operations or, when requested, provide complete incident management functions, including command and general staff, to handle all types of wildland fire risk incidents, anywhere in the country, 24/7/365. When local and regional resources are exhausted, IMTs and other resources, including smokejumpers and airtankers, can be dispatched by the National Multi-Agency Coordination Group, part of the National Interagency Fire Center. Our IMT includes command, general staff, and support personnel from area federal, state, and local government agencies. As a safety officer on the team, it’s my job to oversee all aspects of the incident for risk identification and mitigation, as well as medical contingency planning. Some would say I work for the incident commander; I prefer to say that I work for the firefighters who are at the end of the hose or swinging a pulaski.

Our team had initially been mobilized to the Wallow Fire, a major wildfire near the town of Pinetop, about 200 miles (322 kilometers) northeast of Tucson near the Gila National Forest, but we’d been diverted to this new start. The Monument Fire had only been burning for a couple of days, and we assumed control of it from the extended attack fire organization, which is essentially the local fire department with assistance from federal agencies. We assembled at a local grade school that would be our incident command post for the next couple weeks. I pitched my tent near first base on the school’s baseball field, which had no grass.


Firefighters hose down a home to protect it from a storm of burning embers during a Santa Ana wind-driven wildfire in California. Protecting structures during wildfires is a regular, and increasingly expensive, aspect of firefighting in the wildland-urban interface. (Photograph: Reuters)

Deadline heat
One of the problems with asking wildland firefighters to write articles is that they frequently have to leave their desks to go fight fires, often for weeks at a time.


  • According to the Arizona State Forestry Division, more than $20 million was spent on suppression efforts at the Monument Fire—and that wasn’t even close to being the state’s largest fire of the season. That distinction went to the Wallow Fire, which cost $79 million. Another Arizona fire, the Horseshoe Two Fire, cost more than $50 million to fight.
  • Arizona had $5 million in its fiscal 2011 budget to cover wildfire suppression costs. The federal government pays for fires on federal land, and Arizona is responsible for any fires on 22 million acres (8.9 million hectares) of state trust land and unincorporated private land. Most of this summer’s big fires burned on federal land.
  • Three Fire Management Assistance Grants will cover about three-quarters of the state’s expenses related to the Wallow, Horseshoe Two, and Monument fires that were incurred on state land.
  • Local governments typically pay for operating emergency centers and stepping up patrols to ensure that evacuated areas are protected against criminals, while the state pays for more of the direct costs of battling the wildfires. Arizona’s state government has costsharing agreements with 200 communities to maximize firefighting resources and avoid duplication.
  • Total per-day cost of sending a fire engine with a three-firefighter crew to a wildfire is typically between $2,000 and $3,000.
  • At the peak of the fires in June, a total of 150 trucks worked the Wallow, Horseshoe Two, and Monument fires.
  • Meals, at 8,000 to 9,000 calories a day, cost about $50 a day per firefighter. At its height, the Wallow Fire alone engaged more than 4,000 firefighters.

Sources: Arizona State Forestry Division and The Arizona Republic

We arrived in Arizona in the midst of one of the southwest region’s worst wildland fire seasons on record. A large portion of the nation’s retardant-dropping aircraft, helicopters, hotshot crews, and wildland engines were already deployed to Arizona and New Mexico, where by June 14 nearly 1,500 wildfires had burned, or were still burning, more than 1.2 million acres (485,600 hectares). As I surveyed the Monument Fire that first afternoon, a lot of thoughts and emotions were going through my mind. I recalled the Coronado National Forest’s June update of its fuels advisory summary that I had read a few days earlier:

Fires in May have confirmed conditions. Fires have grown quickly and have been difficult to manage. Aircraft and indirect tactics have been most successful but have still been difficult to manage. Direct tactics have had limited success due to fire behavior and rates of spread. Expect fuels to burn at 100 percent of their potential ERC’s [energy release component] and plan for extreme fire behavior. Several fires in May and early June have grown in excess of 10,000 acres in an afternoon. Make sure good safety zones are established, good burned black or areas completely void of fuel make great safety areas. Maintain good situational awareness at all times and don’t underestimate the fine flashy fuels.

The weather forecast for the following day called for temperatures up to 99°F (37°C), minimum relative humidity from 2–6 percent, with winds in the afternoon reaching 20 mph (32 kph) coming from the west. The extended outlook was much the same. Based on the weather, the Fire Behavior Forecast was for “extreme fire behavior, long range spotting, and quick transitions from surface to crown fire.” There had been no rain for the past six months; fuels were as dry as they could be, and there was abundant fuel loading in the Ash Canyon drainage. The fire was well-established in rugged, mountainous terrain, with drainage and canyon alignment conducive to wind-driven fire runs.

There was a wildland-urban interface (WUI) component to this fire, too. The WUI was comprised of a variety of residential development, typical in WUI areas, from single homes on large parcels to tightly spaced subdivsions with little defensible space. Homes and structures were located in the valley on mostly flat terrain, and many were surrounded by heavy vegetation that had a dry grass understory component and oak brush overstory. Much of the fuel in the area was dead from a frost that occurred earlier in the year, as well as the current drought conditions. When the fire, fed by downslope winds, came into the valley, the fuels carried it to the homes and across roads to other subdivisions that would, under normal conditions, be safe from the fire spread. While we had little time before the fire came out of Ash Canyon, preparation included crews putting in hand line, laying hose lines, and removing volatile fuels from around homes. Additional resources allowed for more preparation around the homes before the next wind event, resulting in fewer structure losses.

The Monument Fire brought together all of the challenges of the WUI: heavy, dry, dead fuels; strong winds; close proximity of fuels to structures; limited water supply, low humidity, and difficult terrain; and topography and weather conditions that limited our ability to establish control lines on the mountain. Multiple fire jurisdictions added to the complexity of communications and command. The stage was set for a “perfect storm” of fire and management conditions.

Preparation + action
In 1967, during my rookie year with the Flathead Hotshots in northwestern Montana, a group of seasoned smokejumpers arrived and gave us wildfire training. A grizzled, solidly built smokejumper gave us our lesson on fire behavior. “Anyone can tell what a fire has done, and most can look at a fire and tell what it is doing — but your challenge to be successful and survive in fighting wildfire is to be able to correctly predict what the fire will do, well before it does it,” he told us. “Pay attention to the signs the smoke is always giving: color, intensity, pulsing or steady, and direction of drift. Pay special attention to the fuels it’s getting into and the topography that will influence its behavior. Constantly monitor the weather’s relative humidity, temperature, and especially the winds.” He was very serious in his presentation. At one point he had tears in his eyes, and he had to stop a minute to regain his composure.

The presenter was Early Cooley, who was the spotter responsible for picking out the jump spot for 15 smokejumpers at the 1949 Mann Gulch Fire in Montana. Twelve of those smokejumpers lost their lives, because collectively they underestimated the fire’s potential behavior. His words of wisdom and his challenge to me, to be well ahead of correctly interpreting wildfire behavior, have stuck with me during my 45 years of wildfire fighting. It is the most important key to remaining safe, and being successful, with suppression strategies and tactics.

I thought about Cooley’s words again that first afternoon when we met with local government officials and agency managers for a short briefing. There, we were given command of the fire, including general incident management, by the U.S. Forest Service and the National Park Service, the federal agencies that administered the land where the fire was burning. The Monument Fire was now in three jurisdictions: Coronado National Memorial, which was administered by the National Park Service; the Coronado National Forest, administered by the U.S. Forest Service; and private lands in the Palominas Fire District. Our control objectives were the protection of public property and firefighter and public safety. We attempted to establish a unified command that would coordinate all agencies involved in fighting the fire, but the local fire departments declined and established their own command structure and staging areas.

The next day, June 14, we assumed management of the more than 130 firefighters already assigned to the fire, mostly local wildland and structure firefighters. Based on the predicted weather and existing fire situation, a lot of additional resources were ordered, including structure and wildland engines, water tenders, hotshot and hand crews, heavy helicopters, and air tankers, much of which had to travel considerable distances to get to the fire because local resources were so strapped. The leadership of our IMT began coordinating efforts with local fire services and emergency management personnel, a process that continued throughout the incident — more than 1,300 firefighters would eventually be involved with the fire.

Using plans formulated the previous night, operations began to deploy engines, crews, and aircraft to implement the initial fire strategy, which was to use fixed-wing retardant and heavy helicopter water drops to try to keep the fire from developing a push down Ash Canyon. At the same time, indirect fuel breaks and firelines were being built at the east-west boundary of private and U.S. Forest Service lands, with the hopes that they could be used to set backfires that would remove much of the available fuel in the fire’s path. Engines did recon in the neighborhoods in case the fire could not be controlled outside the WUI, so that firefighters could familiarize themselves with access and water sources, develop deployment strategies, and identify potential hazards. As the day went on, though, it seemed less likely that we would be able to contain the fire outside the WUI; conditions were too dry and windy with too much volatile fuel, resulting in way too much fire. By mid-afternoon on June 14, there were clear indications we could get some very active fire coming down the canyon, which could threaten homes, residents, and firefighters.

Life safety is the first priority in any fire event, and a public evacuation of more than 10,000 people, out of a population of about 130,000 in Cochise county, was implemented by the county sheriff. The evacuation was recommended by the IMT and local fire officials based on anticipated fire behavior, with the area evacuated being a bit larger than the area where the fire was expected to end up. The WUI provided few safe areas of refuge for fire crews or the public; flame lengths in excess of 50 feet (15 meters) were produced by the heavy dead fuels. In addition to residents, we also had a couple of hundred firefighters (as well as many structures) directly in the path of what could be a major fire run. I’d been constantly scanning the command, tactical, and air-to-ground radio frequencies, and there was a common feeling that the fire was building for a major run down Ash Canyon in the next few hours. On the radio I concurred with operations that we needed to start moving some of our crews off the lines and to safe areas; I told them not to wait until the last minute, that the fire behavior was so extreme that engines and crews should be withdrawn before the fire front hit the WUI. Burning out against an intense, wind-driven fire doesn’t work, and it puts firefighters at great risk.

The engine crews were quickly reassessing their deployment options for protecting homes, options that are based on what the homeowners have given them to work with, coupled with imminent extreme fire behavior. Some homeowners had done a good job clearing out fuels on their property, and others had not — and those properties could be death traps for anyone who chose to stay. As fires intensify, so does the risk to homes and firefighters, so most of the engines retreated to safe zones. The plan was for them to return to neighborhoods as quickly as possible once the fire blew by, to check for ignitions and overall starts. The sooner ignitions are found, the less fire there is that needs to be put out; sometimes it can be put out using only an extinguisher or a backpack water pump. With many more homes in the area than engines, though, those properties that are substantially involved with fire are triaged as “black,” meaning no firefighting effort is given to property already lost.

As we suspected, the fire began its build for a run down Ash Canyon around noon. Fire runs gradually build in intensity, then slow down as they lose energy; they can typically last anywhere from a few minutes to several days. The Ash Canyon run of June 14 went pretty hard for between four and five hours, and was in the subdivisions by mid-afternoon. During the run it burned about 4,600 acres, and destroyed 40 homes and many outbuildings. There were no significant firefighter or civilian injuries. As soon as the fire front passed, engines and crews entered the fire area and triaged structures. They were able to save a number of homes that were partially involved in fire. Later that day, the winds died down, temperatures cooled, and the humidity rose. Those factors, combined with firefighting efforts, checked the fire spread, at least for a while. There would be two additional major fire runs in the days ahead that would repeat this day’s events, including evacuations of residents: one on June 16, and another on June 19, which was pushed by 40 to 50 mph (65 to 80 kph) winds that resulted in additional losses of homes.

Finally, on June 22, we got a break in the weather. The winds died down, which gave us a chance to use the hotshot crews to build a handline with chainsaws, shovels, and pulaskis. The handline extended for six miles (10 kilometers) along the west fire edge, up and over the rugged Huachuca Mountains. Helicopters used water to control the fire perimeter. The fire gradually became contained and then was under control by late June. The Monument Fire ended up involving 30,500 acres (12,343 hectares) and destroyed 60 homes, as well as a number of outbuildings and businesses. The final cost of suppression was more than $20 million, with property damage also in the tens of millions of dollars. Flooding in July and August exacerbated the damage, a result of countryside that had lost its vegetation to fire.

The takeaway: What the Monument Fire tells us about WUI firefighting
In a number of important ways, the Monument Fire highlighted the difficulties associated with firefighting in the WUI.

Weather, fuels, and topography are always key factors in WUI fires. When those conditions align, they can create extreme fire behavior and major control problems for the fire agencies. Usually one of those factors must change before a major WUI fire can be controlled. Without a change in fuel type, a drop in wind speed, or some kind of slope or aspect change in the terrain, control is very difficult, and at times impossible, regardless of the resources available.

Fuels and topography at the Monument fire were unique to the area, but not in the challenges they posed for fighting fire in the WUI. The freezing weather that killed much of the vegetation had set the stage for unprecedented fire behavior in this area. The dead leaves on the oak trees, hot temperatures, and low humidity allowed fire to develop early in the day, and the afternoon winds, combined with the funneling effect of the canyons, created fire conditions akin to a landscape-scale blow torch. These conditions created a flaming front driven by high winds that made it impossible to hold the fire line. The three major runs on the Monument Fire all came out of canyons — Ash, Stump, and Miller. Each of these runs destroyed homes, some of which were more than a mile away in light grass.

As in many WUI fires, those environmental conditions made containment and control of the Monument Fire very difficult. The terrain limited the ability to put in fire lines directly next to the fire edge. Indirect attack — establishing the fire line away from the fire, then burning out the remaining fuels — was difficult to accomplish because of the winds, lack of water, and light flashy fuels next to the line. Adding to the problem was that little fuel mitigation had taken place around the homes, and dry, flammable fuels allowed the fire to ignite homes and other structures. Structure protection included engine crews preparing homes, establishing water supply, and bringing hose lays and portable tanks to areas without hydrants. Hand crews were used to remove fuels around homes and create control lines along roadways. Because of the lack of defensible space, though, the engine crews were forced to withdraw to safe zones until the fire front passed. They immediately returned to their assigned homes and suppressed fires in and around the structures. The engine crews saved many homes from destruction because of aggressive firefighting in difficult conditions.

Complicating the management of this fire was the fact that it involved multiple jurisdictions, which required increased effort for everyone to coordinate operations, tactics, resources, and especially communications. Unified command almost always poses challenges for the fire service, but that’s especially so in the WUI. Local fire departments that work together regularly develop relationships, understandings, and procedures for how they will operate when an incident creates joint responsibilities. These relationships and plans take time to develop before they can be effective. Large WUI events often mean that local agencies are meeting an outside IMT for the first time, and figuring out how to work together can be difficult. An outside IMT often doesn’t know what kind of WUI fire training or experience the local firefighters working for you have; most wildland firefighters, and even more structural firefighters, do not have much practical experience with deploying in the WUI in front of an intense, wind-driven wildfire to protect structures. At the same time, though, local agencies feel a strong responsibility to protect their residents, and the IMT has a delegated responsibility to contain and control the fire and protect the same private property. There’s little time for relationship building, but pre-planning by the local fire agencies can make the integration of an IMT simpler and more effective when fire occurs.  

The Northern Rockies IMT had management responsibility for the fire, but, as with most WUI fires, local agencies bordering the fire also played major roles in protecting their communities. Unified command was offered and encouraged by the IMT — especially as the firefighting force grew to more than 1,300 from an assortment of agencies — but the decision by the local fire agencies to create their own command created a number of problems in how the fire was managed. This situation, which is becoming less common as the unified command approach is more widely embraced, created difficult radio communications, as well as an array of personnel and organizational challenges that led to poor relationships between the various firefighting agencies. Structure protection would have improved with a unified plan.

To that point, the Monument Fire illustrated the extent to which structure protection in the WUI is truly a partnership between homeowners and local fire agencies. Informed homeowners need to prepare their property before the fire arrives, and not expect the fire agencies to do it for them — as many homeowners in the communities affected by the fire apparently believed. Education of proper fire-rated construction materials, as well as landscaping and land management, can help in this preparation. The belief that it is the responsibility of the local fire department to protect private property regardless of fire conditions is irresponsible. The WUI creates a complex assortment of conditions that require a planned response by everyone involved, but the homeowner and local fire department are the primary developers of the plan. The arriving incident management team brings numerous tools to the fire, but it cannot immediately overcome the lack of planning and preparation at the local level.

We wrapped up our Monument Fire operations and returned to Montana on June 30. On September 6, our IMT was mobilized to Hamilton, Montana, in the southwestern part of the state, to manage the 41 Complex Fire, which included three fires that burned a combined 11,500 acres (4,654 hectares) of National Forest land. This time, we were successful in keeping the fires on federal lands. No structures were lost.

Rick Trembath has been fighting wildfires around the country for 45 years. He was also a structure firefighter for 35 years and was chief of Bigfork Fire & Ambulance in Bigfork, Montana. He owns Flathead Forestry & Fire Consulting and teaches WUI courses for the National Fire Academy.

Scott Waldron contributed additional reporting to this story. He has been a wildland and structure firefighter for 25 years and is fire chief in West Yellowstone, Montana. He was the structure protection specialist for the Montana-based IMT1 at the Monument Fire.

Deadline heat 

One of the problems with asking wildland firefighters to write articles, especially during fire season, is that they frequently have to leave their desks to go fight fires, often for weeks at a time. Fire, apparently, has little regard for deadlines. 

Authors Rick Trembath (left) and Scott Waldron on the 41 Complex Fire in Montana. (Photograph: Rick Trembath)

That’s what happened to author Rick Trembath, who was close to finishing this story when he emailed in early September to say that his IMT1 had been deployed to the 41 Complex Fire in southwestern Montana. He wasn’t sure how long he’d be down there, he said, but his plan was to hand the story off to another member of his IMT1, Scott Waldron, who’d also been at the Monument Fire but hadn’t been deployed to the Montana fire. Waldron, Trembath assured me, could handle the remaining writing duties. Waldron emailed to say he’d be happy to fill in some of the missing pieces — only to wire two days later that he, too, had been deployed to the growing 41 Complex Fire. The deadline clock, meanwhile, kept ticking.

Waldron kept chipping away at the piece, though, from the incident command post at fire camp in the Bitterroot National Forest, and within a week had sent us a finished piece. When I called his cell shortly afterward with a followup question, he informed me that he was standing atop a mountain he’d hiked up to serve as a lookout for hotshot crews who were working in a particularly tough patch of terrain with fire nearby. Then he proceeded to answer my questions. Waldron, Trembath, and their fellow firefighters corralled the fire — they were home by September 19 — and Journal got its story. Thank you, gentlemen.

— The editor