Sheltering from burning embers and the Creek Fire at the Mammoth Pool Reservoir Boat Launch, Sept. 5, 2020. Photo by Cameron Colombero, via Mike Ikahihifo.
Most structures that burn in a wildfire are not ignited by direct flame impingement, but by burning embers that are lofted and carried downwind ahead of the fire. At Wildfire Today we first covered the role of embers in igniting structures in 2010, a concept brought into the public consciousness by Jack Cohen, a researcher at the Missoula Fire Science Lab. To reduce the chances of a home burning in a wildfire, the most bang for the buck is to concentrate on the Home Ignition Zone. The flammable material near the structure needs to be modified, reduced, or eliminated to the point where multiple burning embers landing in the zone will not propagate the fire and spread to the structure.
The video below produced by the New Jersey Forest Fire Service elaborates on this concept. It is queued up to 1:42 where the issue is addressed.
We must abandon our expectation that we can suppress 100% of wildfires and reject the false narrative that community protection requires wildfire control. Community wildfire disasters have only occurred during extreme conditions when high wind speed, low relative humidity, and flammable vegetation result in high fire intensities, rapid fire growth rates, and showers of burning embers (firebrands) starting new fires. Fire agencies primarily use wildfire suppression tactics for protecting communities from wildfires. But as we see from current extreme wildfire conditions in California, Oregon, and Washington, fire suppression can quickly become overwhelmed and ineffective.
Wildfires, and thus extreme wildfires, are inevitable. Does that mean wildland-urban (WU) fire disasters are inevitable as well? Absolutely not! WU fire research has shown that homeowners can create ignition resistant homes to prevent community wildfire disasters. How can that be possible?
Paradise, California, off Herb Lane near Skyway in Paradise. From Butte County drone mapping project. November, 2018.
Recall the destruction in Paradise, CA, during the extreme 2018 Camp Fire. Most of the totally destroyed homes in Paradise were surrounded by unconsumed tree canopies. Although many journalists and public officials believe this outcome was unusual, the pattern of unconsumed vegetation adjacent to and surrounding total home destruction is typical of WU fire disasters. In 2020 we see the same patterns of home destruction and adjacent unconsumed vegetation in photos from Malden, WA, and Phoenix, Talent, Blue River, and Mill City OR. Home destruction with adjacent unconsumed shrub and tree vegetation indicates the following:
U.S. Forest Service photo.
High intensity wildfire does not continuously spread through a residential area as a tsunami or flood of flame.
Unconsumed shrub and tree canopies adjacent to homes do not produce high intensity flames that ignite the homes; ignitions can be only from burning embers and low intensity surface fires.
The “big flames” of high intensity wildfires are not causing total home destruction.
The Almeda Drive Fire in the area of Phoenix and Talent in southern Oregon. Image by Jackson County, September 8, 2020.
Surprisingly, research has shown that home ignitions during extreme wildfires result from conditions local to a home. A home’s ignition vulnerabilities in relation to nearby burning materials within 100 feet principally determine home ignitions. This area of a home and its immediate surroundings is called the home ignition zone (HIZ). Typically, lofted burning embers initiate ignitions within the HIZ – to homes directly and nearby flammables leading to homes. Although an intense wildfire can loft firebrands more than one-half mile to start fires, the minuscule local conditions where the burning embers land and accumulate determine ignitions. Importantly, most home destruction during extreme wildfires occurs hours after the wildfire has ceased intense burning near the community; the residential fuels – homes, other structures, and vegetation – continue fire spread within the community.
Uncontrollable extreme wildfires are inevitable; however, by reducing home ignition potential within the HIZ we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem. Unfortunately, protecting communities from wildfire by reducing home ignition potential runs counter to established orthodoxy.
There are good reasons to do “fuel treatments” for ecological and commercial objectives. But the greatest fuel treatment effect on wildfire behavior is within the fuel treatment area; fuel treatments do not stop extreme wildfires. So let’s call a spade a spade and not pretend that many, or even most fuel treatment projects actually reduce home ignition potential during extreme wildfires. Because local conditions determine home ignitions, the most effective “fuel treatment” addressing community wildfire risk reduces home ignition potential within HIZs and the community. Wildfires, exacerbated by climate change, will occur. Community destruction during extreme wildfires will continue as long as wildfire suppression remains the primary approach for community protection. Conducting the same ineffective strategy and tactics expecting different results will continue to be a recipe for disaster when it comes to protecting homes from extreme wildfire.
To make this shift, land managers, elected officials, and members of the public must question some of our most deeply ingrained assumptions regarding fire. For the sake of fiscal responsibility, scientific integrity, and effective outcomes, it’s high time we abandon the tired and disingenuous policies of our century-old all-out war on wildfire and fuel treatments conducted under the guise of protecting communities. Instead, let’s focus on mitigating WU fire risk where ignitions are determined – within the home ignition zone.
Jack Cohen, PhD, retired US Forest Service Research fire scientist determined how structures ignite during extreme wildfires, created the home ignition zone concept, and co-developed NFPA Firewise USA.
Dave Strohmaier is Missoula County Commissioner. He previously worked for both the Bureau of Land Management and US Forest Service in fire management, and has published two books on the subject of wildfire in the West.
Above: Dr. Jack Cohen makes a presentation at the 2011 Fire Litigation Conference in San Diego. Photo by Bill Gabbert.
Dr. Jack Cohen received the first National Legacy Award given by the U.S. Forest Service, National Association of State Foresters, National Fire Protection Association, and International Association of Fire Chiefs in recognition of outstanding career-long contributions to wildfire mitigation as an alternative to suppression. Dr. Cohen helped develop the U.S. National Fire Danger Rating System and developed calculations for wildland firefighters’ safe zones; created defensible space principles, which resulted in the Firewise program; the Home Ignition Zone; and conducted research on ember ignitions and structure ignitability.
His research laid the groundwork for nearly all of today’s work on wildland urban interface risk reduction. Until his 2016 retirement, he was a research scientist at Missoula Technology and Development Center. The award was presented at the IAFC WUI Conference in Reno, Nevada.
Thanks and a tip of the hat go out to Robert. Typos or errors, report them HERE.
Above: One of the homes that survived the Eiler Fire in northern California, August, 2014. Photo by Bill Gabbert.
The CBS TV show 60 Minutes recently aired a story titled, “Wildfires on the rise due to drought and climate change“, concentrating on how to deal with the increasing number of wildfires, and particularly what homeowners can do to protect their investments.
Below is an excerpt from the transcript:
Events like [the Yarnell Hill Fire that killed 19 member of the Granite Mountain Hotshots] add urgency to the work at a U.S. Forest Service lab. In this building in Missoula, Montana, scientists study how fires spread.
And one of them, Jack Cohen, made a specialty of how to better defend homes.
Jack Cohen: Clearly we’re not gonna solve the problem by telling people they’re gonna have to move their houses into a city from being out in the woods.
Steve Inskeep: Not gonna happen.
Jack Cohen: Right? It’s not gonna happen for a whole bunch of reasons, one of which is that the population who live there, including me– aren’t gonna do it.
Steve Inskeep: Is it reasonable for a homeowner in that situation, a fire bearing down on their neighborhood to just say, “Look, I pay my taxes. There are firefighters, there’s a fire department. The forest service, if it’s public land, has thousands of firefighters. It’s their job; put it out?”
Jack Cohen: So what if they can’t? Then the question becomes one of, “Well, if the extreme wildfires are inevitable does that mean that wildland-urban fire disasters are inevitable?” And my answer to that is no.
Ember shower on a structure. Screen grab from the NFPA video.
Jack Cohen, a research physical scientist with the U.S. Forest Service, has spent much of his career studying how structures ignite during wildfires. In this video produced by the NFPA, Mr. Cohen expounds on that topic and talks about the actions that homeowners can take to help their home survive the impacts of flames and embers.
The Atlantic has produced two very good pieces on wildland fire.
One is the video below, about research into the science of combustion and how fires spread. It was filmed at the Missoula Fire Sciences Laboratory and has excellent production values and photography. Some of the researchers featured will be familiar to those who follow the topic; they include Mark Finney, Jack Cohen, and Sarah McAllister.
The other is a long-form article about the Yarnell Hill Fire that killed 19 members of the Granite Mountain Hotshots June 30, 2013. There have been several similar articles, but this one, written by Brian Mockenhaupt, is better researched and written than some. In addition to describing the fire, and the fire fight, It includes information about what went on behind the scenes at various dispatch and coordination levels, as well as the personal lives of the firefighters.
Here is a brief excerpt:
“To our families and friends, we’re crazy,” [Crew Superintendent] Eric Marsh wrote in the spring of 2013, in a sort of Granite Mountain manifesto addressed to the town of Prescott. “Why do we want to be away from home so much, work such long hours, risk our lives, and sleep on the ground 100 nights a year? Simply, it’s the most fulfilling thing any of us have ever done.”
[…]
Marsh took the lead in hiring new recruits, and focused as much on character as on stamina. “When was the last time you lied?” he asked in every interview. “Tell me about that.” Truth telling was a guiding principle for Marsh. He had quit drinking more than a decade earlier, and being honest with himself and others had become a big part of his sobriety.
[…]
Like many others who fought the Yarnell Hill Fire and who knew the hotshots who died, [Prescott Fire Department Wildland Division Chief] Darrell Willis has spent a lot of time asking himself why they did what they did. Part of the answer he’s come up with involves the very natural urge to fight and protect our own. “They wanted to reengage,” he said, standing by the posters. “Sure, they could sit up there in the black. But if they could try to get back in the game, they were going to. What they had been doing was lost. And that happens a lot. You put a day’s worth of work into something, and all of the sudden it’s gone, and you have to have a new starting point somewhere. There’s a lot of sweat and expended energy. So what do we do, just sit up here and watch it go by? They knew there was an evacuation going on, they knew there were people staying in their houses. So what would the public think? ‘You’re not going to help us? Why did you even show up?’ ”
President Obama has released his proposed budget for fiscal year 2013. At this point it is merely a suggestion until Congress passes appropriation or spending cap bills.
The budget fully funds the 10-year average cost of wildland fire suppression operations, but there is a reduction in the funding of the treatment of hazardous fuels — by 24% in the Department of Agriculture and by 21% in the Department of Interior.
The numbers in the table below are in millions, and represent the proposed wildfire budgets for the U.S. Forest Service and the four land management agencies within the Department of Interior.
2012
2013
Change
USFS Preparedness
1,004
1,001
-3
USFS Suppression
853
931
+78
USFS Hazardous Fuels
317
242
-75
USDA State & Volunteer Fire Assistance Grants
99
84
-15
DOI Preparedness
277
280
+3
DOI Suppression
81
277
+196
DOI Hazardous Fuels
183
145
-38
DOI Rural Fire Assistance (was $7 million in 2011)
0
0
0
In the Department of Interior’s justification for the 21% reduction in the hazardous fuels budget, they invoked the name of a U.S. Forest Service researcher, Jack Cohen, who has studied the wildland urban interface:
The Wildland Fire Management account in DOI supports wildland fire preparedness, suppression, rehabilitation, and hazardous fuels reduction activities. When targeted properly, hazardous fuels reduction activities (e.g., removing brush and small trees in strategic locations) can reduce impacts from wildfires, including threats to public safety, suppression costs, and damage to natural and cultural resources.
DOI and the Department of Agriculture’s Forest Service have agreed on several actions to reduce impacts from wildfires, such as: 1) prioritizing fuels treatments that have been identified as key components of Community Wildfire Protection Plans and are cost effective; and 2) expanding wildland fire use as a means of treating fuels.
Although funding for hazardous fuels treatments has quadrupled since 2000, the previous policy of treatingthe greatest number of acres possible has led to a patchwork of hazardous fuels treatment that has not been as focused as it could have been on reducing risks in the WUI. As suggested by Forest Service scientists, extensive wildland vegetation management does not effectively change whether or not homes in the WUI catch on fire. However, when there is a clear priority of treating acres within the WUI, hazardous fuels treatments can be more effective in reducing risk.
1,2 In 2013, the Forest Service and DOI will target fuels management activities to mitigate hazards and enhance the ability to control fires in WUI. The agencies will focus funding for hazardous fuels treatments in communities that are on track to meet Firewise standards and have identified acres to be treated in Community Wildfire Protection Plans (or the equivalent) and have made an investment in implementing local solutions to protect against wildland fire.
The Department of Agriculture explained their reduction in the U.S. Forest Service’s hazardous fuels budget, saying that “though the majority of the inexpensive locations have now been treated to reduce hazardous fuels, FS is also furthering its efforts to focus its hazardous fuels treatments in the Wildland-Urban Interface in areas that are identified in Community Wildfire Protection Plans and are highest priority.”
