March 12, 2018

UA Study Suggests Large Wildfire Seasons May Become More Common

TUCSON, Ariz. — While 2017 was an exceptional wildfire year in some respects, new research from the University of Arizona suggests that similar years are likely to become more common.

The massive wildfires that burned in California, Oregon, Montana, Idaho, British Columbia and other parts of North America in 2017 in many cases continued a disturbing trend: a marked increase in the amount of area burned. A new study finds that states in the interior Western U.S., in particular, may be faced with large increases in total wildfire area burned, potentially beyond anything that has been experienced in the past.

Donald Falk, a professor in the UA College of Agriculture and Life Sciences, and co-investigator Thomas Kitzberger, a former visiting scholar at the UA who is now at the Universidad Nacional del Comahue in Argentina, analyzed 34 years' worth of climate data to calibrate area burned across western North America. Taking into account geographic variation, the study data focused on fire occurrence, seasonal temperatures and snowpack.

Summer temperatures during fire season, spring temperatures and rainfall, and winter temperatures are the seasonal climate variables that drive the amount of area burned. Winter and spring conditions regulate snowpack, which can delay the onset of the fire season.

The team built a statistical model for wildfire area burned and then tested it with data for actual area burned since 2010 to validate its predictions. Findings for western and northern North America show that about half the states and provinces are projected to have a large increase — five or more times the current levels — in total wildfire area burned.

"Ultimately, this means that the large fire seasons of recent years, such as the one just ending, are likely to occur more frequently, affecting ecosystems, communities and public safety," Falk said. "These will be billion-dollar fire years. We're just not ready for fire impacts of this kind, including post-fire effects from flooding after fire."

Falk pointed out that seasonal climate changes also are having the effect of making the fire season longer, so there is additional time for more acreage to burn. In those cases, fire management resources may be stretched to the limit.

"We hope that this research will be a wake-up call to public agencies and legislatures at all levels of government that the fire problem is not going to get any smaller in coming decades," Falk said. "If anything, we need a serious, fact-based national dialogue about how to sustain our forests and woodlands through smart management and policy."

The UA's Thomas Swetnam, Regents' Professor Emeritus of Dendrochronology, and Leroy Westerling of the University of California, Merced, were part of the research team, which published "Direct and indirect climate controls predict heterogeneous early-mid 21st century wildfire burned area across western and boreal North America" in PLOS ONE in December.

To read the complete UA News story: https://uanews.arizona.edu/story/wildfire-problem-will-get-bigger-coming-decades

To access the research paper: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0188486

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Media Contact:
Stacy Pigott
UA Communications
520-626-4405
spigott@email.arizona.edu

Established in 1885, the University of Arizona, the state's super land-grant university with two medical schools, produces graduates who are real-world ready through its 100% Engagement initiative. Recognized as a global leader and ranked 16th for the employability of its graduates, the UA is also a leader in research, bringing more than $622 million in research investment each year, and ranking 21st among all public universities. The UA is advancing the frontiers of interdisciplinary scholarship and entrepreneurial partnerships, and is a member of the Association of American Universities, the 62 leading public and private research universities. It benefits the state with an estimated economic impact of $8.3 billion annually.