Researchers recommend amount of fire clearance around structures

Researchers have concluded that the most effective fire clearance or defensible space around structures, to reduce the chances of them burning in a wildfire, is between 16 and 58 feet.

Below is an excerpt from the abstract of a paper written by Alexandra D. Syphard, Teresa J. Brennan, and Jon E. Keeley, submitted to a journal September 16, 2014.

We analysed the role of defensible space by mapping and measuring a suite of variables on modern pre-fire aerial photography for 1000 destroyed and 1000 surviving structures for all fires where homes burned from 2001 to 2010 in San Diego County, CA, USA. Structures were more likely to survive a fire with defensible space immediately adjacent to them. The most effective treatment distance varied between 5 and 20 m (16–58 ft) from the structure, but distances larger than 30 m (100 ft) did not provide additional protection, even for structures located on steep slopes.

Two of the three authors are public employees, so the taxpayers already paid for this research. However, if you want a copy of The role of defensible space for residential structure protection during wildfires, it will cost you $25.

More about Open Access to research that is paid for by taxpayers.



Study: Risk factors for injury among federal wildland firefighters

A student working on her PhD at the University of Iowa wrote her dissertation in 2010 after studying the records of injuries to wildland firefighters. Carla Lea Britton titled her paper “Risk factors for injury among federal wildland firefighters“. We will not attempt to summarize the entire document, but below are some quotes that we thought were interesting in the Conclusions section:


P. 67: The wildland fire community should expand its focus beyond the investigation of fatalities and embrace new methodologies to evaluate and mitigate the impact of non-fatal occupational injuries in wildland fire.

P. 70: Comprehensive surveillance: The resources currently available to estimate and evaluate the burden of injury in firefighters are found in a diversity of situations and are not, in many cases, suitable for linking. Fire managers should work toward developing a new comprehensive occupational injury surveillance system to capture fire-related injuries, illness and fatalities across the spectrum of wild- and prescribed fires, training activities and types of employment.

P. 70-71: Partnerships: Guidance on the safety and health of wildland firefighters is provided by the NWCG’s Safety and Health Working Team (SHWT). The SHWT’s mission is to improve health and safety through workforce development, leadership and the development of standards using data collection and analysis to validate and prioritize safety issues. While the mission is commendable, the SHWT lacks both the resources and expertise to fully realize its goal. The SHWT is comprised of representatives from the NWCG member agencies. Most of the committee members are the national-level fire safety managers for the agencies they represent. While all have extensive backgrounds in fire suppression, few, if any, have any formal training in occupational health and safety. The SHWT should actively pursue partnerships with either the National Institute for Occupational Safety and Health or with university-based researchers to provide additional expertise, particularly in the area of injury epidemiology and prevention, topics on which there have been little research emphasis in the past.

P. 71-72: This project has shown that, even with sub-optimal data collected for other purposes, systematic evaluation of existing data can provide useful hints for prevention and point to areas where further inquiry is likely to be fertile. To move forward, the wildland fire community needs to commit to using existing data to the best advantage possible and to developing new surveillance methods to provide comprehensive information about all wildland firefighter injuries and their circumstances.


Thanks and a tip of the hat go out to Kevin.


Recording of webinar on the effectiveness of suppression resources in large fire management

UPDATE, October 22, 2014: The Wildland Fire Lessons Learned Center uploaded a better, higher-resolution version of the video. We replaced their original version we had earlier embedded, with the improved one you see above.  


This video is a recording of an October 8, 2014 webinar on the effectiveness of firefighting resources in suppressing large fires. I hesitated to embed it here because about a third of the dozens of the graphics are illegible. They only use a portion of the available screen and the resolution is very low. Expanding the video to full-screen does not help. However, the content is interesting.

Here is how the webinar topic was described:

Dave Calkin presents on webinar on October 8, 2014. Wildfire management currently represents over 50 percent of the US Forest Service’s total budget. Suppression of large fires represents the single largest category of fire management and typically exceeds $1 billion annually. In both 2012 and 2013 large fire suppression exceeded the Agency’s budget allocations by over $400 million. Despite the scale of this investment relatively little is understood about how suppression actions influence large wildfire spread and those conditions that ultimately lead to containment. There is considerable uncertainty in managing large wildfires including the quality of weather forecasts, complex environmental conditions, variation in the type and quality of suppression resources, and whether or not requested suppression resources will be assigned.

In this presentation we review several recent studies that attempt to understand how suppression actions influence fire progression as well as review variation among Incident Management Teams in the amount of resources that they use to manage large wildland fires in the US. Despite these recent efforts, there remains limited understanding of suppression effectiveness. These results suggest that modeling large fire containment as a production process of fireline construction similar to traditional initial attack models is inappropriate. Improved understanding of large fire management effectiveness and efficiency will require spatially tracking individual resource assignments, activities, and tactics within the broader suite of fire management objectives and strategies.

One of the key facts the researchers needed in their study was how resources assigned affected the containment of the fire.

The National Wildfire Coordinating Group defines “contaiment”:

The status of a wildfire suppression action signifying that a control line has been completed around the fire, and any associated spot fires, which can reasonably be expected to stop the fire’s spread.

It is well known that many incident management teams do not accurately report the daily containment percentage, usually pulling a number out of their rear end that is much lower than the actual amount of fireline that is constructed. They don’t have the courage to report the facts so they lie, fearful that if there is competition for resources a lower containment percentage will enable them to obtain and sometimes hoard firefighters, crews, engines, and aircraft — regardless, in some cases, of greater needs elsewhere. On a fire we visited in 2013 managed by a Type 1 incident management team we found that even though it had been contained for a couple of days, and there was very little mopup that still needed to be done, the Incident Commander reported a very low containment percentage in order to make it easier to justify an evacuation order to the public.

The researchers realized this, so they ignored the official percentages reported on the daily Incident Status Summary report, the ICS-209. They analyzed fires for which perimeter maps were available for each day. When a section of the fire perimeter stopped moving permanently, for the purposes of their study they considered that area “contained”.

They found that on 50 fires they looked at, when the entire perimeter stopped moving the average containment reported was 64 percent. Of course, there may be good reasons for not declaring a section of line held or contained. It may not move in that area, but it could still require fireline to be constructed. Reasons for a fire to stop moving other than proactive suppression, include changes in weather, fuels, and topography.

So it is not possible, using ICS-209s or mapping data after the fact, to accurately determine the actual containment of a fire. However, the method used by these researchers may provide a figure closer to reality than the data reported by many incident management teams.

Geographic Area Coordinating Centers and Multi-Agency Coordinating Groups that have to allocate scarce resources may be tempted to use the method described in this webinar to truth-check the information reported by incident management teams.


Second generation of Simtable being developed

In May we recorded the video above and told you about the Simtable which projects 3-D wildfire simulations onto a sand table which can be molded to resemble the topography in a specific area.  Fire modeling algorithms simulate the spread of fire through the vegetation and across the topography while also taking weather and fuel conditions into account. You can simulate a fire at your choice of location, or you can view the spread of historic fires. The system can also be used to simulate and train for evacuations, floods, and hazardous material incidents — at a starting price of $25,000.

A researcher at San Diego State University is developing the next generation of the Simtable which he hopes to put into the hands of wildland firefighters out on the ground.

10News reports:

“Any firefighter with a smartphone or tablet could download it and have the mapping system,” said [Justin Freiler of SDSU’s Visualization Center].

They are not there yet, as a mobile app is still in development, but the hope is to make the system available to firefighters in the near future.


International researchers study fire in New Jersey’s Pine Barrens

In 2014, with assistance from the New Jersey State Forestry Services, U.S. Forest Service and international researchers from the United Kingdom and Russia teamed up to collect data on a prescribed fire in the Pine Barrens of New Jersey. The fire’s embers, or commonly known as fire brands, were one important aspect of the study.