Western wildfire smoke plumes are getting taller.
In recent years, the plumes of smoke crawling upward from Western wildfires have trended taller, with more smoke and aerosols lofted up where they can spread farther and impact air quality over a wider area. The likely cause is climate change, with decreased precipitation and increased aridity in the Western U.S. that intensifies wildfire activity.
“Should these trends persist into the future,” says Kai Wilmot, a postdoctoral researcher in the Department of Atmospheric Sciences at the University of Utah, “it would suggest that enhanced Western U.S. wildfire activity will likely correspond to increasingly frequent degradation of air quality at local to continental scales.”
“Given climate-driven trends towards increasing atmospheric aridity, declining snowpack, hotter temperatures, etc. We’re seeing larger and more intense wildfires throughout the Western U.S., and this is giving us larger burn areas and more intense fires.”
To assess trends in smoke plume height, Wilmot and U colleagues Derek Mallia, Gannet Haller and John Lin modeled plume activity for around 4.6 million smoke plumes within the Western U.S. and Canada between 2003 and 2020. Dividing the plume data according to EPA ecoregions (areas where ecosystems are similar, like the Great Basin, Colorado Plateau, and Wasatch and Uinta Mountains in Utah) the researchers looked for trends in the maximum smoke plume height measured during August and September in each region in each year.
In the Sierra Nevada ecoregion of California, the team found that the maximum plume height increased, on average, by 750 ft (230 m) per year. In four regions, maximum plume heights increased by an average of 320 ft (100 m) per year.
Why? Wilmot says that plume heights are a complex interaction between atmospheric conditions, fire size and the heat released by the fire.
“Given climate-driven trends towards increasing atmospheric aridity, declining snowpack, hotter temperatures, etc., we’re seeing larger and more intense wildfires throughout the Western U.S.,” he says. “And this is giving us larger burn areas and more intense fires.”
The researchers also employed a smoke plume simulation model to estimate the mass of the plumes and approximate the trends in the amount of aerosols being thrown into the atmosphere by wildfires . . . which are also increasing.
The smoke simulation model also estimated the occurrence of pyrocumulonimbus clouds—a phenomenon where smoke plumes start creating thunderstorms and their own weather systems. Between 2017 and 2020, six ecoregions experienced their first known pyrocumulonimbus clouds and the trend suggests increasingly frequent pyrocumulonimbus activity on the Colorado Plateau.
Taller plumes send more smoke up into higher elevations where it can spread farther, says John Lin, professor of atmospheric sciences.
“When smoke is lofted to higher altitudes, it has the potential to be transported over longer distances, degrading air quality over a wider region,” he says. “So wildfire smoke can go from a more localized issue to a regional to even continental problem.”
Are the trends accelerating?
Some of the most extreme fire seasons have occurred in recent years. So does that mean that the pace of the worsening fire trend is accelerating? It’s too early to tell, Wilmot says. Additional years of data will be needed to tell if something significant has changed.
“Many of the most extreme data points fall within the years 2017 -2020, with some of the 2020 values absolutely towering over the rest of the time series,” he says. “Further, given what we know of the 2021 fire season, it appears likely that analysis of 2021 data would further support this finding.”
In Utah’s Wasatch and Uinta Mountains ecoregion, trends of plume height and aerosol amounts are rising but the trends are not as strong as those in Colorado or California. Smoke from neighboring states, however, often spills into Utah’s mountain basins.
“In terms of the plume trends themselves, it does not appear that Utah is the epicenter of this issue,” Wilmot says. “However, given our position as generally downwind of California, trends in plume top heights and wildfire emissions in California suggest a growing risk to Utah air quality as a result of wildfire activity in the West.”
Wilmot says that while there are some things that people can do to help the situation, like preventing human-caused wildfires, climate change is a much bigger and stronger force driving the trends of less precipitation, higher aridity and riper fire conditions across the West.
“The reality is that some of these [climate change] impacts are already baked in, even if we cut emissions right now,” Wilmot adds. “It seems like largely we’re along for the ride at the moment.”
Find the full study at Nature.com.
Cyri Dixon has been named a NACADA Outstanding New Advisor.
Cyri Dixon, the Undergraduate Academic Advising Coordinator for the Department of Physics & Astronomy, has won the Outstanding New Advisor Award – Primary Role Category – from the National Academic Advising Association (NACADA). Award selection is extremely competitive and designed to honor and recognize professionals who have made significant contributions to the field of academic advising in higher education. Candidates are nominated by their institution, and each application is carefully reviewed by NACADA committee members. All outstanding advisor nominations include a comprehensive list of the nominee’s professional qualifications, academic accomplishments, letters of support, and documented advising success.
“I am grateful to work with such fantastic students, staff, and faculty. Advising is challenging, but working with my wonderful students makes it all worth it.”
“I am very honored to receive this award,” said Dixon. “I am grateful to work with such fantastic students, staff, and faculty. This award really highlights the strides we have been able to make in our department to create a better student experience and build a community where all students feel welcome and successful. Advising is challenging, but working with my wonderful students makes it all worth it.”
Dixon was previously recognized for her exemplary advising work when she was named Outstanding New Academic Advisor in 2021 by the University of Utah Academic Advising Community (UAAC). She serves as the only undergraduate advisor for the department and has proven to be a valuable resource to undergraduate physics students in all areas of academic advising. She has 236 physics major students that she meets with regularly, and she takes pride in knowing each student by name. She helps each develop a course plan that fits their interests, and she connects them to research and internship opportunities, campus resources, and the department community.
Here are comments from the University of Utah’s President’s Office, faculty, staff, and students about Dixon and her work:
“Dear Cyri, The President’s Office received this email of gratitude from a parent recognizing the talented staff and student employees at our university. Thank you for the hard work, kindness, and caring dedication you show our students and families. You are appreciated, and we value your contribution to the success of our students and university. We know this comes from colleagues like you who make it happen. Thank you.”
~Office of the President
“Whenever I am worried about a student, Cyri knows what is going on or knows what to do to address the problem. Thank you for your help, patience, and for caring about all our students.”
~Dr. Tugdual Stephan Lebohec, faculty
“Cyri’s work represents many of NACADA’s Core Values, but most striking is her laser-like focus on empowering her students. In her philosophy, Cyri shares a little of her own experience as a first-generation student from a rural area; knowing that there so many talented and brilliant students who are limited in opportunities and resources, she [Cyri] writes that this ‘drives my motivation to help any student who walks in my door to not only survive and graduate, but also thrive and make the most of their experience.’”
~Stephanie Begaye, and Ashley Glenn, UAAC Advisor Awards Committee Co-Chairs
“Cyri has been a terrific advisor for me. She has always been available for chats or emails and been quick to respond to all of my questions, even unusual or specific ones that are only tangentially related to completing a physics degree. After every meeting I’ve had with her, I tell my wife, ‘she’s a great advisor.’ I think Cyri absolutely deserves this award.”
“Cyri, thank you for taking the time to write a letter of recommendation on my behalf. I wanted to let you know I was accepted into two programs, one of them being the University of Utah! This is a huge step in pursuing my career goals and an immense accomplishment for me.”
A first-generation graduate of Utah State University, with a degree in Physical Sciences Education, Dixon also has minor degrees in physics and chemistry teaching. She recently earned a Master of Public Administration degree from the University of Utah. Originally from Idaho, she returned to Utah after living in the Midwest and teaching middle school science and engineering in Arizona. She loves hot air ballooning, Wonder Woman, and her dog, Roka.
Since 1983, NACADA has honored individuals and institutions making significant contributions to the improvement of academic advising. The goal of NACADA is to promote quality academic advising and professional development of its membership to enhance the educational development of students. For more information, visit NACADA.
Josh Steffen, Ph.D.SRI Director; Associate Professor Lecturer
Heather Briggs, Ph.D.SRI Associate Director; Associate Instructor
Ryan M. Stolley, Ph.D.SRI Associate Director; Associate Instructor
Laura RupertSRI Project Coordinator