NIST Study Leads to Recommendations for WUI Fires
"Our study showed that WUI fires also are distinct from either urban or wildland fires alone. We provide strong evidence that defensive measures designed specifically for the wildland urban interface and administered early can significantly reduce destruction and damage," said NIST fire researcher and principal investigator Alexander Maranghides.
The Commerce Department's National Institute of Standards and Technology has completed a study of Colorado's 2012 Waldo Canyon wildfire near Colorado Springs and has concluded that prompt, effective response can significantly change the outcome of wildland urban interface (WUI) fires -- ones that occur in areas where residential communities and undeveloped wildlands meet. Now NIST has offered recommendations to firefighters based on the findings.
"WUI fires are very different from earthquakes, hurricanes, and tornadoes where the hazard cannot be controlled," said NIST fire researcher and principal investigator Alexander Maranghides. "Our study showed that WUI fires also are distinct from either urban or wildland fires alone. We provide strong evidence that defensive measures designed specifically for the wildland urban interface and administered early can significantly reduce destruction and damage."
The researchers found that because the Waldo firefighters tailored their response to the specific WUI conditions, 75 percent of their attempts to extinguish ignited structures were successful and 79 percent of their efforts at fire containment were successful in preventing rampant fire spread. NIST released the study results Nov. 9 during the Fire Chiefs White House Roundtable on Climate Change Impacts at the Wildland Urban Interface.
According to the agency, the number of WUI fires is rising as housing developments push into wilderness areas. According to the Bureau of Land Management's National Interagency Fire Center, the 10 years since 2002 saw an annual average of nearly 71,000 WUI fires recorded and 4.7 million acres burned. More than 32 percent of U.S. housing units and one-tenth of all land with housing are located in the nation's 220 million acres of WUI, putting approximately 72,000 communities and more than 120 million people at risk, it says.
The Waldo Canyon fire started on June 23, 2012. By the time it was declared contained on July 10, 2012, it had killed two people dead, destroyed 344 homes and damaged more than 100, burned 18,247 acres, and cost an estimated $454 million in insured losses.
Key findings from the study:
- WUI fire dynamics change rapidly and require special consideration. "For example, if your home is nestled deep within a neighborhood away from the leading edge of a fire, you might not be at risk early on," Maranghides said. "However, the danger to your home dramatically increases if a neighboring house, the surrounding landscape, or a nearby vehicle catches on fire."
- WUI fires create "cascading ignitions," meaning their intensity, spread, and destructive power increase rapidly as more and more structures are ignited.
- Defensive measures were very effective in suppressing burning structures and containing the Waldo Canyon fire; firefighters could contain fire spread because they effectively assessed fire behavior, exposure risks to structures from fire and embers, and potential responses by structures to the changing conditions.
- There was not a nationally accepted system available for preplanning the response to the Waldo Canyon event, and the researchers believe pre-fire planning could have further enhanced the response.
Key technical recommendations they made include these:
- Fire departments should develop, plan, train, and practice standard operating procedures for responding to WUI fires in their communities.
- A "response time threshold" for WUI fires should be established for each community.
- High-density structure-to-structure spacing in a community should be identified and considered in WUI fire response plans.