Are there 4 or 5 common denominators of fire behavior on fatal fires?

Our article about adding to the list of common denominators of fatal fires led someone to ask in a comment, “When and why was Wilson`s 5th Common Denominator dropped ?”

In 1976 four firefighters were entrapped on the Battlement Creek Fire, killing three near what is now Parachute, Colorado. Following the tragedy, Carl C. Wilson, who at one time was the Chief of Forest Fire Research at the U.S. Forest Service’s Pacific Southwest Forest and Range Experiment Station, published a paper titled Fatal and Near-Fatal Forest Fires: The Common Denominators.

Carl WilsonIn developing his paper, Mr. Wilson studied 67 fires that occurred during the 61-year period from 1926 to 1976 on which a total of 222 firefighters were killed from “fire-induced injuries”. He also evaluated 31 other “near-fatal” fires, searching for common themes or causes of the deaths in all of the fires. His results were considered ground-breaking. Since then his lists of Common Denominators have been republished, quoted in fatality reports, and included in many standard publications that are very familiar to firefighters.

When we listed his Common Denominators in the January 29 article we used the four that are seen in all of the recent and semi-recent publications that we looked at, including the last paper version of the Fireline Handbook (2004), the 2014 Incident Response Pocket Guide, and the report authored by Dick Mangan, Wildland Firefighter Fatalities in the United States: 1990-2006. The only revision of the Fireline Handbook since 2004 was completed in 2013 and was renamed Wildland Fire Incident Management Field Guide (PMS 210). It does not include the Common Denominators. The 2004 and 2006 editions of the Incident Response Pocket Guide also include the four-item list.

After a great deal of searching we found that there is another list of Common Denominators attributed to Mr. Wilson that has similar but different wording, and has five instead of four. The five-item list was in a 2011 paper by by Martin E. Alexander and Miguel G. Cruz and also in the 1998 version of the Fireline Handbook.

Finally we found a copy of Mr. Wilson’s paper, Fatal and Near-Fatal Forest Fires: The Common Denominatorsthat was published in 1977 in The International Fire Chief. It has two different lists.

The first, the five-item list, is printed on the first page just below the heading “Common Denominators of Fatal Fires”.  Here is the text just below that heading:

“Based on personal knowledge and information obtained from reports and reviewers, the following generalizations can be made about the fatal fires in Tables 1 and 2 [tables 1 &b 2 are fatal fires]:

  1. Most of the incidents occurred on relatively small fires or isolated sectors of larger fires.
  2. Most of the fires were innocent in appearance prior to the “flare-ups” or “blow-ups”. In some cases, the fatalities occurred in the mop-up stage.
  3. Flare-ups occurred in deceptively light fuels.
  4. Fires ran uphill in chimneys, gullies, or on steep slopes.
  5. Suppression tools, such as helicopters or air tankers, can adversely modify fire behavior. (Helicopter and air tanker vortices have been known to cause flare-ups.)”

A key to that list is that it only applies to the 67 fatal fires he studied, and not the 31 that were near-fatal.

Toward the end of the paper in the “Conclusions” section, Mr. Wilson wrote:

“There are four major common denominators of fire behavior on fatal and near-fatal fires. Such fires often occur:

  1. On relatively small fires or deceptively quiet sectors of large fires.
  2. In relatively light fuels, such as grass, herbs, and light brush.
  3. When there is an unexpected shift in wind direction or in wind speed.
  4. When fire responds to topographic conditions and runs uphill.” 

We’re not sure why Mr. Wilson broke down the common denominators into fatal and near-fatal fires. I don’t know that it adds value, but can, and has, produced a little confusion when two different versions of the lists are floating around.

Wildland Fire Incident Management Field Guide eBook available for download

The reincarnation of the Fireline Handbook, now saddled with the name Wildland Fire Incident Management Field Guide, is now available as an eBook for your Apple and Android devices. The January, 2014 revision is described on the Google Play store as “scanned pages”, and is designed for tablets or the “web”.

I downloaded the Android version and viewing it in a web browser on a 20-inch monitor was not a satisfying experience. It looked like a low-resolution scanned document. However on a 7-inch Nexus tablet the text was small when viewing an entire page, but it was very sharp and quite readable. Flipping from page to page was easy as pie. It would probably be even better on a larger tablet but don’t even think about trying to read it on a smart phone.

The Fireline Handbook, last revised in 2004, was officially retired in 2013 and replaced with an electronic version, a .pdf, of the Wildland Fire Incident Management Field Guide (PMS 210). The National Wildfire Coordinating Group explained last year why they created the new publication:

The document was renamed because, over time, the original purpose of the Fireline Handbook had been replaced by the Incident Response Pocket Guide. As a result, this document now serves as a guide for wildland fire managers and subsequent staff.

The January, 2014 revision of the Incident Response Pocket Guide is available for download as a .pdf document.

Fighting fire in a beetle-killed forest

Mountain Pine Beetle, matchWhen a forest that has been attacked by pine beetles is on fire, there is a lot that we do not know about the flammability, crown fire potential, and resistance to control of these burning stands of conifers. Testing the torching potential of individual beetle-killed crowns was conducted in the winter over a ground covered with snow using a propane burner as the heat source. Flammability of vegetation has been evaluated in a lab. But it has not been proven that existing fire spread models can accurately predict the rate of spread of a stand of trees that has been attacked by pine beetles. As the authors of the paper below stated:

It is a shocking admission that the only empirical investigation of fire behaviour in live, lodgepole pine stands is limited to a single study, involving surface fires, carried out in British Columbia, Canada, 45 years ago (Lawson, 1972;1973).

In an effort to summarize what we do and do not know, three scientists, Wesley G. Page, Michael J. Jenkins, and Martin E. Alexander, collaborated on a paper titled Crown fire potential in lodgepole pine forests during the red stage of mountain pine beetle attack. The entire paper can be read here — their conclusions are below:



True insight into understanding and predicting the possible effects of recent [Mountain Pine Beetle] MPB-caused tree mortality on surface and crown fire potential in lodgepole pine forests has so far proven to be largely an intractable problem. While significant progress has been made in recent years documenting the effects of MPB-related tree mortality on fuel complex structure as well as seasonal and diurnal fuel moistures, trying to accurately assess potential fire behaviour using either operational or physics-based fire behaviour models has proven problematic. Except for the recent development in British Columbia, Canada, with respect to astatisticalmodel(Perrakis et al., 2012), existing models tend to be either inappropriate and/or un-validated for use in MPB-attacked forests. Current operational fire behaviour models used in the US are not capable of addressing the complex spatial arrangements of crown fuels that occur in recently attacked stands. Physics-based models such as WFDS may in time serve to be useful research tools and aid in understanding the dynamic nature of fire behaviour, but until the limitations and sources of error are better understood, interpretations of the resulting simulations must be viewed with scepticism (Alexander and Cruz, 2013a).

Observations from experimental fires and wildfires indicate that a real and considerable increase in crown fire potential exists in recently attacked stands with an increase in rate of spread on the order of 2 –3 times the no-tree mortality predictions. However, the amount of red foliage within the canopy has important implications on the duration of the increased crown fire hazard. Site-specific factors such as the total and yearly amount of tree mortality, the length of the outbreak, and the preexisting stand conditions could all be important factors that could affect the severityand duration of the crown firehazard. Additional factors such as the juxtaposition of red and green crowns and the relative importance of needle drop and subsequent decreases in CBD vs the increased flammability of red foliage may be important to evaluating crown fire hazard but as yet are not fully understood.

Limitations in the ability to accurately assess crown fire potential in MPB-affected stands are likely to persist until accurate wildfire observations and/or experimental fires can be used to either validate current fire behaviour models or derive the needed empirical proportionality constants in VanWagner’s (1977) crownfire initiation and propagation models applicable to MPB-attacked stands. A program of experimental fires (Alexander and Quintilio, 1990; Stocks et al., 2004a) coupled with more systematic monitoring and documentation of wildfires (Alexander and Taylor, 2010) is needed in order to address these current shortcomings and gain insight into the underlying processes controlling fire behaviour in MPB fuel complexes. It is a shocking admission that the only empirical investigation of fire behaviour in live, lodgepole pine stands is limited to a single study, involving surface fires, carried out in British Columbia, Canada, 45 years ago (Lawson, 1972;1973). Additional information on the physical processes of foliage ignition and the relative effect of moisture content under varying heat fluxes will also aid in the development and modification of physics-based models that would greatly enhance our understanding of fire behaviour in these forest ecosystems (Ma¨kela¨ et al., 2000).

As the number and size of MPB outbreaks in western North America declines, opportunities to conduct experimental fires and observe fire behaviour in recently attacked stands will decrease. Simulating MPB-attack, similar to Schroeder and Mooney (2009; 2012), by girdling trees provides a potential way to extend the window of opportunity for experimental fires and to control for confounding factors. Investments in gathering and compiling fire behaviour data by fire management and fire research organizations will help provide a means to objectively assess fire behaviour potential in this unique fuel complex, which will increase the margin of safety for future wildland firefighters and aid in operational planning for fire managers. Meanwhile, wildland firefighters should continue to be vigilant in recently attacked MPB-affected lodgepole pine forests and follow the guidelines outlined in the fire environment factors listed in the ‘Look Up, Down and Around’ table for insect-killed forests found in the Incident Response Pocket Guide (National Wildfire Coordinating Group, 2010).”

Two NPS employees receive Paul Gleason awards

Chad Fisher and Jim Shultz,. NPS, received Paul Gleason award
Chad Fisher and Jim Shultz of the NPS received Paul Gleason Lead By Example awards

From the NPS Morning Report:


“Two staff members from the National Park Service Branch of Wildland Fire were recently awarded the prestigious Paul Gleason Lead by Example Award for 2013. The intent of this award is to recognize individuals or groups who exhibit Gleason’s professional spirit and who exemplify the wildland fire leadership values of duty, respect, and integrity.

Chad Fisher, wildland fire safety program manager, and Jim Shultz, wildland fire training program manager, each received the award. Only three individuals and one group from across the wildland fire service were chosen to receive this national award for 2013.

“To have not just one, but two employees, honored with this interagency award, really highlights the caliber of work and leadership by NPS wildland fire management staff,” said acting National Park Service Wildland Fire Branch Chief Mark Koontz. “Chad and Jim are outstanding representatives in their respective fields.”

bootsIn addition to his mission, vision, and dedication to ensuring that firefighter safety is always the number one objective on all assignments and every fire, regardless of size or complexity, Chad Fisher was recognized for his work with the Dutch Creek mitigations. Chad’s actions to reach across agency boundaries have contributed to a shift in culture regarding incident-within-an-incident planning. His dedicated effort to ensure  that staff  understand, weigh, and communicate the consequences of placing firefighters in harm’s way to decision-makers, along with  ensuring that there is a mechanism to evacuate injured firefighters, sets the example for all to follow.

He was also commended for his work with firefighter nutrition, the Incident Response Pocket Guide revision, leadership development activities, facilitated learning analyses, and serious accident investigation teams. Chad’s leadership exemplifies the values of duty, respect, and integrity.

Jim Shultz was recognized for his ability to develop subordinates across agency boundaries through programs like the Fire and Aviation Mentoring program and the National Interagency Joint Apprentice Committee. As memorial group supervisor for the Honor Guards and Pipes and Drums, Jim’s calm demeanor and leadership skills helped ensure all honor guards worked together to make the Granite Mountain Hotshot Memorial Serviceas seamless as possible.

As an advocate for leadership development, Jim seeks improvement and develops others for the betterment of the individual as well as the team and organization. This has been shown through field assignments and pioneering the wildland fire leadership and career development video series to help young firefighters answer questions regarding the rights steps to take toward a permanent career as a wildland firefighter. Jim exemplifies the values of duty, respect and integrity.

The award was created by the NWCG Leadership Subcommittee to remember Paul Gleason’s contributions to the wildland fire service. During a career spanning five decades, Paul was a dedicated student of fire, a teacher of fire, and a leader of firefighters. The intent of this award is to recognize individuals or groups who exhibit this same spirit and who exemplify the wildland fire leadership values of duty, respect and integrity.

Congratulations to Chad and Jim on their achievements.”


Last year the awards were presented to Anthony Escobar, John Lauer and Shane Olpin.

State analysis of Yarnell Hill Fire fatalities proposes $559,000 fine for Arizona State Forestry Division

Yarnell Hill Fire at 1549 June 30
Yarnell Hill Fire at 1549 June 30, 2013. Photo by Chris MacKenzie of the Granite Mountain Hotshots. The arrow represents the location where the lookout had been positioned earlier.

(Originally published at 2:46 p.m. MT December 4, 2013; updated at 8:30 p.m., December 4, 2013)

Today the Arizona Division of Occupational Safety and Health (ADOSH) proposed fines totaling $559,000 to be imposed on the Arizona State Forestry Division as a result of the fatalities on the Yarnell Hill Fire near Yarnell, Arizona. Their findings were presented to the Industrial Commission of Arizona during a 1:00 p.m. public meeting in Phoenix. The documents can be found HERE.

On June 30, 19 members of the Granite Mountain Hotshots were entrapped by rapidly spread flames from a brush fire and were killed. One member of the crew who was in a different location serving as a lookout was not injured.

Two citations were proposed, one “willful serious” with a tine of $545,000, and another that was “serious” with a fine of $14,000.

[UPDATE at 6:46 p.m. MT December 4, 2013; The commission approved the fines. The Arizona State Forestry Division has 15 days to appeal the decision.]

The willful serious citation included the following (paraphrased):

  • Failure to furnish a place of employment which was free from recognized hazards that were causing or likely to cause death or serious physical harm.
  • Implementation of suppression strategies that prioritized protection of non-defensible structures and pastureland over firefighter safety.
  • The employer knew the suppression was ineffective, and that the wind would push the fire toward non-defensible structures, but firefighters were not promptly removed from exposure to smoke inhalation, burns, and death.
  • Thirty-one members of a structure protection group charged with protecting non-defensible structures were exposed to possible smoke inhalation, burns, and death.
  • A lookout was exposed to the same dangers.
  • Approximately 30 firefighters working on an indirect fireline in Division Z were exposed to the same dangers.
  • The Granite Mountain Hotshots continued with suppression activities until 1642 hours on June 30 when they were entrapped by a rapidly progressing wind driven wildland fire.

The serious citation, totaling $14,000:

  • The employer failed to implement appropriate fire suppression plans in a timely fashion during a life-threatening transition between initial attack and extended attack.
  • When the fire escaped initial attack none of the following analysis procedures were implemented: Incident Complexity Analysis, Escaped Fire Situational Analysis, Wildland Fire Situation Analysis, Wildland Fire Decision Support System, or Operational Needs Assessment.
  • On June 29 an Incident Action Plan was not completed for the next operational period prior to transitioning to a more complex management team.
  • The positions of Safety Officer and Planning Section Chief were not filled on June 30.
  • On June 30 the Division Z Supervisor (adjacent to the Granite Mountain Hotshots’ Division) departed from his assigned position which left Division Z without supervision during ongoing fire suppression operations.

Today, in addition to the citation information, the following documents were released by the Industrial Commission of Arizona:

We will add to this article later with more details about the investigation report, but below are the conclusions reached by Wildland Fire Associates, the consultants hired by the Arizona Division of Occupational Safety and Health:

  • Fire behavior was extreme and exacerbated by the outflow boundary associated with the thunderstorm. The Yarnell Hill Fire continually exceeded the expectations of fire and incident managers, as well as the firefighters.
  • Arizona State Forestry Division failed to implement their own extended attack guidelines and procedures including an extended attack safety checklist and wildland fire decision support system with a complexity analysis.
  • The incident management decision process failed to recognize that the available resources and chosen administrative strategy of full suppression and associated operational tactics could not succeed. This also remained the case when the strategy changed from full suppression to a combination of point protection and full suppression.
  • Risk management weighs the risk associated with success against the probability and severity of failure. ASFD failed to adequately update their risk assessment when the fire escaped initial attack leading to the failure of their strategies and tactics that resulted in a life-threatening event.


UPDATE at 8:30 p.m. MT, December 4, 2013

We just finished reading the “Inspection Narrative” compiled by AZ OSHA, and the “Granite Mountain IHC Entrapment and Burnover Investigation” report written by Wildland Fire Associates (WFA).

The Inspection Narrative

We noticed a couple of interesting tidbits in the Inspection Narrative that we don’t remember being pointed out in the previous Serious Accident Investigation Team report which was released on September 28.

One was found on page 18. At approximately 1545 hours, one of the the Type 2 Operations Section Chiefs called the Granite Mountain Hotshots and asked if they could spare resources to assist in Yarnell. Either Marsh or GMIHC Captain Steed responded that they were committed to the black and he should contact the Blue Ridge Hotshots.

While the GMIHC said they were not available for the change in assignment, the request from the Ops Chief informed them that they were needed in Yarnell. This may have influenced their decision to move toward the ranch, perhaps with the ultimate goal of assisting in the town. We could not find a mention of this in the WFA report.

One other item in the Narrative (on page 17) we noticed was a disagreement and/or confusion about the break between Divisions A and Z. The Division Z Supervisor didn’t arrive on the fire line until 1 p.m. on June 30. I in addition to the Division break fiasco, he was not clear at all about what tactics in the area could be successful. He left the fire line to head to the Incident Command Post and did not return. Parts of this were also mentioned in the WFA report. The problem with filling the Division Z position was mentioned in the citation.

Below are some quotes from the WFA report:

P. 15: At 1558, ATGS abruptly leaves the fire and goes to Deer Valley. He turned air tactical operations over to ASM2 who was busy dealing with lead plane duties at the time. ASM2 got a very brief update from ATGS that did not include division breaks locations and the location of the on-the-ground firefighters. ASM2 had been ordered as a lead plane because ATGS functions were covered.
Continue reading “State analysis of Yarnell Hill Fire fatalities proposes $559,000 fine for Arizona State Forestry Division”

National firefighter safety stand down, July 3, 2013

The National Multi-Agency Coordinating Group in a July 2 memo asked for a safety stand down, or operational pause, for the morning of July 3, 2013:


“National Firefighter Operational Safety Stand-down Tomorrow

NMAC Operational Pause

National Interagency Fire Center, 3833 S. Development Avenue, Boise, Idaho 83705

July 2, 2013

To: Geographic Area Coordination Centers

From: National Multi Agency Coordinating Group

Subject: July 3, 2013 Operational Pause in Remembrance

The wildland fire community, and the nation, deeply mourn the loss of nineteen firefighters from Prescott Fire Department’s Granite Mountain Interagency Hotshot Crew. Even as we mourn this tragic loss we must also remember and honor the other firefighters who have perished in the line of duty on other wildland fires this year.

The 2013 fire season is well underway and is likely to continue at a high intensity level for several more months. With that in mind, NMAC requests that all wildland fire personnel in the United States observe an Operational Pause in Remembrance on the morning of Wednesday, July 3.

As we remember our fallen, we must also consider those who survive and the challenges they face in dealing with the magnitude of such a loss. Agency leaders must make available the kinds of counseling and peer support that can help employees work through their emotions. The goal is to reduce the potential long-term impacts that are sometimes a consequence of normal human reactions to tragedy. Some wounds cut deeper, and take longer to heal, than others.

An operational pause is also a time for thoughtful reflection about risk (see “Resources” below). It is a time-out from daily operations – even while committed to an incident. It is a time to focus exclusively on the kind of work we do, our operational environment and the hazards we encounter there, how we assess risk, and the risk mitigations that can be employed to reduce risk to acceptable levels. It is a time to recognize the implications of the fact that in the hazardous wildland fire environment, risk can never be reduced to zero even with the best mitigation measures in place. It is a time to reflect on the fact that we can always take an operational pause to consider these things, even during high-tempo operations.

We ask that all fire managers and fire personnel take the time to thoughtfully take an Operational Pause in Remembrance. And we thank all firefighters and support personnel for their efforts.

/s / John Segar

Chair, NMAC