This story appeared in the Spring 2021 Letters & Science magazine.
About one in four people in the United States lives in an area served by cellular phone towers at risk of an outage caused by wildfires, according to a recent study by Paul Barford, a UW-Madison professor of computer sciences, and Carol Barford, who directs UW–Madison’s Center for Sustainability and the Global Environment. More than 430,000 cell network transceivers covering approximately 85 million people are in areas the U.S. Forest Service considers at moderate or high wildfire risk, the researchers found. Their study suggests ways to make the sites more fire-hardy.
“This is a kind of road map for cell service providers to make assessments, allocate resources and take steps to make their infrastructure more resilient in the face of this threat,” says Paul Barford. The two also collaborated on a 2018 project describing how thousands of miles of fiber-optic cable in the U.S. are likely to be inundated by rising sea levels. Wildfire danger has a distinctly different footprint and presented a complex set of prediction problems.
“Fires are a fact of life for many ecosystems,” says graduate student Scott Anderson, first author of the study, which was supported by the National Science Foundation and the U.S. Department of Homeland Security and presented at the ACM Internet Measurement Conference. “Assessing the risk of fire, though, is complex. It varies a lot over time based on the amount of fuel available, how dry that fuel can get as climate changes, and almost unpredictable factors like the source of ignition.”
The researchers worked with historical records of wildfires, and matched the Forest Service’s map of Wildfire Hazard Potential to a crowdsourced database of cellular network equipment locations from OpenCelliD.
Six states—California, Florida, Texas, South Carolina, Georgia, and North Carolina—each have at least 5,000 transceivers in high-risk areas.
“We think of the wildfire threat as being concentrated only in the western part of the United States,” Anderson says. “But we did see that there are areas that are at risk outside of the West, including the southeastern United States—especially in Florida—and even up around Philadelphia.”
The threat will only grow as climate change makes many areas more fire prone, and as more Americans make their homes near the cusp of both wilderness and civilization.
“The areas that need the most attention are those where urban growth has gotten very close to forests and other sources of fuel for wildfires,” Paul Barford says.
Key among the researchers’ recommendations for protecting cellular networks: emergency power.
“Cell towers in high-risk areas all need to have backup power—battery backup or generator backup—that can enable them to continue to operate,” Barford says.
The stakes can be high. More than 80 percent of California’s 911 calls come from cellphones, and cellular networks are vital to first responders trying to contain a fire and organize in an emergency.
