It’s not news to Coloradans that wildfire frequency and intensity are increasing, destroying homes and sometimes claiming lives. Wildfire mitigation currently focuses on suppression and managing wildland fuel, but these strategies are not enough. A new study by Hussam Mahmoud, associate professor of civil and environmental engineering, shows there’s a better way to protect communities from wildfires than this one-size-fits-all approach.
Mahmoud’s research, published in the Royal Society Journal, found that many factors determine a community’s risk, including wind speed and direction, pattern of surrounding wildland vegetation, and building layout. He and co-author Akshat Chulahwat quantified wildfire risk to several communities for the first time, based on these factors.
“Right now, if a community wants to mitigate the impact of wildfire, they’re told to do the same thing: have defensible space, cut vegetation in the area surrounding your home, reduce fuel built up in the wildland, and you should be good,” Mahmoud said. “What we clearly showed in this paper is that’s not necessarily the answer.”
While these mitigation measures help, he said, they’re not the most optimal nor cost-effective. No two communities are the same, and each requires its own solution.
A custom approach
Mahmoud and Chulahwat, a Ph.D. candidate in Mahmoud’s research group, evaluated wildfire risk for four real communities. Surprisingly, they found ignition probability, or the likelihood of a fire starting in surrounding wildland, was not the most important indicator of risk. It was just one among several significant factors.
“You don’t necessarily see correlation between ignition probability and vulnerability and risk,” Mahmoud said. “If I increase one and lower the other, or increase the other and lower the first one, I still get the same level of risk.”
To calculate a community’s vulnerability, they considered the various ways in which fire spreads. They examined wind data from May through September and looked at the distribution of homes, and how the homes were oriented with respect to both wildland and wind.
Even in areas with high ignition probability, a community’s risk might remain low if there’s no wind to push fire toward the community. On the other hand, if homes are densely arranged, fire is more likely to jump from one home to the next, causing widespread damage.
Considering the complex interplay of all the factors together enabled Mahmoud and Chulahwat to a create custom assessment for each community.
“You have to look at all these things combined to have a risk-informed plan that will work for communities,” Mahmoud said.
Mahmoud hopes policy makers and stakeholders will be able to use their analysis to better plan for the future and mitigate wildfire impact at the community level. By applying the model they’ve developed, decision makers can see how much each mitigation technique could lower their community’s risk. It also will allow them to save money by targeting resources toward the most effective methods.
As communities grow and climate change exacerbates wildfires, risk assessment and mitigation strategies are more important than ever.
“I can’t see this going away any time soon,” Mahmoud said. “We have to learn how to live and deal with these fires.”