Arizona prepares for worsening wildfire seasons

The Goodwin Fire burned 28,516 acres near Prescott in June and July 2017. Wildfires are predicted to burn larger swaths of Arizona and other western states every year as the climate changes. (Photo courtesy of the Arizona Department of Forestry and Fire Management)

A record-breaking fire season in 2017 – with massive fires across California, Montana, Idaho, Oregon and British Columbia – is likely only the beginning of a trend of worsening wildfire seasons in western North America, according to a recent study published by a team of university researchers.

According to the December study in the journal PLOS ONE, parts of Idaho, Montana, Wyoming, Utah, Colorado, New Mexico, Arizona and Nevada are likely to see increases of five or more times the current levels of area burned each year by 2038. Other areas studied ranged from greater than two times area burned and small increases, to even small decreases in some parts of the Arctic.

“It’s a wake-up call to be ready,” said Don Falk, an associate professor in the University of Arizona’s School of Natural Resources and the Environment and an author of the study. “The fire phenomenon is not going to go away, it’s going to get bigger.”

The researchers compared 34 years of data on seasonal temperature, rainfall and snowpack with acreage burned each year in western North America to understand how climate affected the area burned in the past. They then built a statistical model using future climate projections to predict how area burned each year is likely to change between now and 2038.

“The first premise we took is that we’re not going to get a single equation that answers the seasonal response to fire,” Falk said. To account for this, the researchers divided the study area into 1,500 grid cells and studied each area separately.  “If you look at the projections, we see some areas that are very different.”

The huge variation in different areas is a result of the length and severity of the fire season and the availability and flammability of fuels. These are both affected by many complex and localized seasonal climate factors, Falk said.

Seasonal temperatures and rainfall affect plant growth and moisture levels, which influence how likely it is that an area will burn. More rainfall usually means more plant growth, but also that plants are less dry and therefore less flammable. “There’s kind of a balance between the two,” Falk said.

As the climate warms and dries, fire seasons are likely to start earlier and end later. “There are a lot of indications that fire season is getting longer everywhere,” Falk said.

Falk noted that more area burned doesn’t necessarily mean more severe wildfires in terms of impacts to humans and ecosystems.

Falk and the research team chose not to predict beyond 2038 because researchers aren’t confident they can accurately forecast climate in the latter half of this century.

“It’s not just going to be climate alone, but climate times fire times insect outbreaks and other things,” Falk said. “There’s a good chance that a lot of the landscape by the end of the century will look very different. It could be a different biome.”

Fire prevention in Arizona: a statewide response

Arizona Gov. Doug Ducey announced in February that he will double the amount of money he asks the Arizona State Legislature for fire prevention. It will increase from $1 million to $2 million for fiscal year 2019.

“After experiencing an unusually dry winter, we need to commit to giving the Department of Forestry and Fire Management the tools they need to prevent and battle these catastrophic fires,” Ducey said in a news release.

Karl Gehrke, a planning specialist with the department, said that focusing on fire-prevention activities, like tree thinning and prescribed burning, will be key as fire conditions worsen across the state in the coming years and decades.

According to Gehrke, spending on fire prevention can save huge sums of money in the long run. Fighting fires is much costlier than preventing them. Gehrke said that the 2017 Goodwin fire in Prescott cost about $20 million to fight, but he thinks it could’ve been avoided with $2 million dollars in prevention work.

“We need to be doing that work now regardless of the cost,” Gehrke said. “The cost down the road will be 10 to 20 times more.”

Ducey’s request for a doubling of fire prevention funds still needs to be passed by the state Legislature. The money, if awarded, wouldn’t come in until the beginning of the next fiscal year in July, which is usually after the worst of Arizona’s fire season. The money would be used for fire prevention in the 2019 fire season.

As for the 2018 season, Gehrke says that low precipitation this winter, and winds that prevented some planned prescribed burns are “putting us further behind than we would like to be.” He’s optimistic, though, and thinks that the department will be prepared for this fire season because it has agreements with almost all of the fire departments across the state. Arizona’s fire season usually comes earlier than in other states, also, meaning that fire crews from other states can be called in to help.

“When there’s a fire it’s pretty much all hands on deck,” Gehrke said.

Falk said that increases in spring and summer temperatures, and decreases in spring precipitation, are likely to have the biggest impact on annual area burned in Arizona.

A March report by the National Oceanic and Atmospheric Administration predicts increased temperatures and drought for Arizona and other southwestern states in spring 2018. Increased spring and summer temperatures and decreased spring precipitation are the climate variables most likely to increase annual area burned in Arizona, according to Falk. (Graphic by: NOAA)


More fire fighting and prevention, or better land-use planning?

Although fire fighting and prevention are important, Falk says that climate change could alter landscapes and increase annual area burned so much that traditional methods of fire prevention and suppression might not cut it. He’d like to see more emphasis on land-use planning that avoids building in areas that are likely to burn.

“You could do fuel treatments, you could have suppression activities, that’s all great, but climate could override all of those things,” Falk said. “… At a certain point, there needs to be a serious discussion about where we put these people’s lives and infrastructure in relation to this fairly inevitable occurrence.”

Michaela Webb is a reporter for Arizona Sonora News, a service from the School of Journalism with the University of Arizona. Contact her at

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