The report also describes how the NIST-USFS WUI Hazard Scale provides a state-of-the-art tool for making such assessments and how that data could be linked to improved building codes, standards and practices that will help communities better resist the threat of wildfires.
The Witch Creek/Guejito WUI fire (commonly known as the Witch Fire) was the largest of a series of wildfires that began burning across Southern California on Oct. 20, 2007. It affected areas north and northeast of San Diego, starting in Witch Creek Canyon near Santa Ysabel and quickly spreading westward toward the coast because of strong Santa Ana winds. The Witch Fire burned some 80,000 hectares (nearly 200,000 acres), destroyed more than 1,600 structures, caused an estimated $1.8 billion in property damages and cost $18 million to fight. It also was responsible for two civilian deaths and 39 firefighter injuries.
A NIST-USFS WUI team worked in collaboration with the California Department of Forestry and Fire Protection (CAL FIRE) and the City of San Diego to collect post-incident data within the Witch Fire perimeter. The team focused its effort on The Trails development at Rancho Bernardo, north of San Diego. There were 274 homes in The Trails, with 245 within the fire perimeter. Seventy-four homes were completely destroyed and 16 were partly damaged. Field measurements made by the NIST team included structure particulars, specifically roof type; proximity of combustibles to the structure; and damage to wildland and residential vegetation. Documentation included more than 11,000 photographs.
The data collected and analyzed were used in two separate NIST-USFS reports. The first, issued in 2009, created a detailed timeline of the Witch Fire, tracked its impact on the community, and documented defensive actions taken by homeowners and first responders. The latest study evaluates the effectiveness of those mitigation techniques addressing exposure risks—as defined by the WUI Hazard Scale—associated with direct fire contact and ignition by embers.
"This is the first time anyone has looked at wildfire impact by evaluating pre-event exposure risks throughout an entire community and how those risks affected the defensive actions that were in place," says Alexander Maranghides, lead author of both Witch Fire reports.
What the researchers found was that the majority of defensive strategies used in The Trails were effective and that the level of effectiveness was correlated to fire and ember exposure. Damage and destruction were more prevalent in structures assessed by the WUI Hazard Scale as having been at highest risk from fire and embers. Accordingly, defensive actions were more than twice as effective in saving structures in low-exposure sections of the community as compared to high-risk areas.
Maranghides says that a pre-event knowledge of exposure risks also may be helpful in determining how firefighters attack a WUI fire. "Our data show that it's probably best to fight fires in low-exposure areas because there's a greater chance that they can be suppressed and with less danger to the crews," he explains. "It may be better to sacrifice structures in high-exposure areas than risk the loss of firefighter lives in unwinnable situations."
1) The newest study: A. Maranghides, D. McNamara, W. Mell, J. Trook and B. Toman. A Case Study of a Community Affected by the Witch and Guejito Fires: Report #2 – Evaluating the Effects of Hazard Mitigation Actions on Structure Ignitions. NIST Technical Note 1796 (2013) at http://nvlpubs.nist.gov/nistpubs/TechnicalNotes/NIST.TN.1796.pdf
2) Announcement of the NIST/USFS WUI Hazard Scale: "NIST, Forest Service Propose System to Help Communities Resist Wildfires," NIST Tech Beat, Dec. 12, 2012. http://www.nist.gov/el/fire_research/fire-121212.cfm
3) First NIST study of the Witch fire: "NIST Study Offers First Detailed Look at the Progress of a Wildland-Urban Fire," NIST Tech Beat, June 16, 2009. http://www.nist.gov/el/fire_protection/wui/fire_061609.cfm
* USFS defines the wildland urban interface, or WUI, as an "area where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels."
Michael E. Newman | EurekAlert!
The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses