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Research: Why Wildfires Become Disasters

February 07, 2017

University of Idaho researchers and their international partners have conducted an unprecedented global study that establishes where mega-wildfires occur and why they become disasters. This research initiates new conversations on the important topic of how communities can better prepare for fire. The findings were published yesterday in the scientific journal Nature Ecology and Evolution.

Around the world, large and intense wildfires are destroying homes and resulting in the deaths of firefighters. While such disasters frequently make headlines, historically scientists have not had a global database to help them understand why these extreme wildfires occur and what can be done to lessen the consequences to communities.

The team includes assistant professor Crystal Kolden and associate professor Alistair Smith in the UI College of Natural Resources Department of Forest, Rangeland and Fire Sciences; John Abatzoglou, an associate professor in the UI College of Science Department of Geography; and researchers from the University of Tasmania in Australia and South Dakota State University.

The research team analyzed 23 million wildfire events around the globe that occurred from 2002-2013. From this database, they focused on the top 478 most intense fire events. Of these, the team found that approximately 30 percent were disastrous fires for humans.

The researchers found that extremely intense fires like this are usually associated with weather events such as drought, high winds or, in the case of desert ecosystems, after seasons of particularly wet weather produced a high amount of new vegetation. The disastrous events primarily occurred where humans have built semi-rural communities in highly flammable landscapes, like dense forests.

“What is really novel about this study is that in the U.S., we tend to make the assumption that all large and intense fires are disasters, and that there is nothing we can do about it,” Kolden said. “But that is not the case at all. What makes a fire event a disaster in the U.S. is when key factors combine – low density housing amidst dense forests, the right climatic conditions, and a lack of fire preparedness on the part of humans.

“We can't stop big, intense fires from happening here, and they are increasing under climate change. However, in the western U.S., we can reduce the potential for fire disasters by both reducing forest density and improving mitigation and preparedness through the development of fire-resilient communities.”

According to Kolden, the U.S. had a much higher proportion of fire events become disasters than any other country in the study. Wildfire burned more than 10 million acres in the U.S. in 2015, and cost over $2 billion to suppress. Most U.S. area burned is in the western states and Alaska.

One example of a disastrous fire in the database is the Elk Complex Fire, which burned over 130,000 acres and destroyed 38 homes near Mountain Home, Idaho, in 2013. The Elk Complex Fire burned so hot that scorched soils contributed to numerous mudslides when the fall rains came, endangering Anderson Ranch Reservoir. 

The study concludes that there is an urgent need for communities to become more resilient in the face of wildfire. Some of this work will require a cultural shift in the way people think about investing in fire preparedness.

“In areas prone to earthquakes, there are standards and regulations in place for planning and building to address those risks, and there is an economic cost associated with those standards,” Smith said. “In order for communities to be able to live with these extreme fires, we will need new building materials and innovative zoning, landscape, and construction solutions to make communities more resilient to these disastrous wildfire events. As we already do with earthquakes, local and national governments are going to have to be willing to bear the burden of what it costs to enable communities to thrive in the face of these inevitable disasters.”

Study lead author David Bowman, professor of Environmental Change Biology at the University of Tasmania, agrees with Smith’s assessment.

 “Planning, regulation and enforcement by government, along with awareness and investment by individual citizens living in fire-prone areas will be necessary for positive changes to occur.  There are no simple solutions; we will have to change our behaviors and there are significant economic costs – we have a big mountain to climb.”

The team also noted that additional research efforts that focus on ways to optimize human community resilience to fire are critical.

CNR faculty members are already working on these challenges; they are planning a workshop in June in Ketchum, Idaho, that will focus on bringing together community members and leaders and fire science experts to create solutions that address the specific needs of the community. The goal is to create a workshop model that can be replicated anywhere in the U.S. and will be relevant to needs of communities.

“As a leader in fire science research, the University of Idaho is dedicated to producing solutions that help communities in our state, across the American West and around the globe address the critical problem of disastrous wildfires,” said UI vice president for research and economic development Janet Nelson. “Our innovative, interdisciplinary researchers examine wildfire patterns, pursue methods to reduce risk and severity, and collaborate with communities to prepare for fires.”

The paper, “Human exposure and sensitivity to globally extreme fire events,” is available online.

Media Contacts
Kim Jackson
Marketing and Communications Manager, College of Natural Resources

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The University of Idaho, home of the Vandals, is Idaho’s land-grant, national research university. From its residential campus in Moscow, U of I serves the state of Idaho through educational centers in Boise, Coeur d’Alene and Idaho Falls, nine research and Extension centers, plus Extension offices in 42 counties. Home to nearly 12,000 students statewide, U of I is a leader in student-centered learning and excels at interdisciplinary research, service to businesses and communities, and in advancing diversity, citizenship and global outreach. U of I competes in the Big Sky and Western Athletic conferences. Learn more at