Evans School of Public Policy & Governance

This research effort tackles the challenges that simultaneous megafires currently pose to decision makers and stakeholders, and supports proactive planning for future scenarios to mitigate risk (NSF Growing Convergence Research #2019762). Megafires are fires that are unusually large or that require a complex and aggressive firefighting response because of dramatic threats to lives, property, and/or infrastructure. When multiple megafires occur simultaneously, firefighting resources may be strained beyond capacity with catastrophic results. To successfully advance the frontiers of fire science and management to mitigate risk at the intersection of natural and human systems, we are developing a highly convergent approach in a team comprised of researchers from University of Washington, NCAR (National Center for Atmospheric Research), and University of California, Merced. We bring expertise in decision science, climate science, statistics, and fire science to our collaboration with on the ground decision makers including fire managers, fire ecologists, and land managers for tribal and US government agencies.

We aim to strengthen risk management related to wildfire impacts with improved climate projections in support of decisions regarding land use, fuel and land management, and wildfire suppression, thereby helping to safeguard against the future loss of life, property, infrastructure, and natural resources.

Please contact Alison Cullen  alison@uw.edu  with questions or to inquire about partnership opportunities. 

Data Visualizations

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Peer Reviewed:

    1. Bloem S, Cullen AC, Mearns LO, Abatzoglou, JT. (2022) “The role of international resource sharing arrangements in managing
      risk from simultaneous wildfire in the face of climate change” Fire, accepted for publication June 2022.
    2. Hawkins LR, Abatzoglou JT, Li S, Rupp DE. (2022) “Anthropogenic influence on recent severe autumn fire weather in the west coast of the United States” Geophysical Research Letters 48(8).
    3. Gaines W, Hessburg P, Aplet G, Henson P, Prichard S, Churchill D, Jones G, Isaac DJ, and Vynne, C. (2022) “Climate change and the Northwest Forest Plan: managing for dynamic landscapes.” Forest Ecology and Management 504: 119794. Online: https://doi.org/10.1016/j.foreco.2021.119794.
    4. Jain, P, Castellanos-Acuna, D, Coogan, SCP., Abatzoglou, JT & Flannigan, MD “Observed increases in extreme fire weather driven by atmospheric humidity and temperature.” (2021). Nat. Clim. Chang. doi:10.1038/s41558-021-01224-1 Online: https://www.nature.com/articles/s41558-021-01224-1
    5. Abatzoglou, JT, Battisti, DS, Williams, AP et al. “Projected increases in western US forest fire despite growing fuel constraints.” (2021). Commun Earth Environ 2, 227. https://doi.org/10.1038/s43247-021-00299-0
    6. Abatzoglou, JT, Cullen, AC and Prichard, S, Synchronous fires and fire danger challenge US capacity to respond, The Climate Circulator, September 29, 2021, https://climatecirculatororg.wordpress.com/2021/09/29/synchronous-fires-and-fire-danger/
    7. Prichard SJ, Hessburg PF, Hagmann RK, Dobrowski S, Povak NA, Hurteau MD, Kane VR, Keane RE, Kobziar LN, Kolden CA, North M, Parks SA, Safford HD, Stevens JT, Yocom LL, Churchill DJ, Gray RW, Huffman DW, Lake FK, and Khatri-Chhetri P. (2021). “Adapting western North American forests to climate change and wildfires: ten common questions” Invited feature. Ecological Applications. Online: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/eap.2433.
    8. Abatzoglou JT, Rupp DE, O’Neill LW and Sadegh M. (2021). “Compound Extremes Drive the Western Oregon Wildfires of September 2020” Geophysical Research Letters 48(8) Online: https://doi.org/10.1029/2021GL092520
    9. Abatzoglou JT, Juang CS, Williams AP, Kolden CA and LeRoy Westerling A. (2021). “Increasing synchronous fire danger in forests of the western United States” Geophysical Research Letters 48(2) Online: https://doi.org/10.1029/2020GL091377
    10. Cullen AC,  Axe T and  Podschwit H. (2020) “High-severity wildfire potential – associating meteorology, climate, resource demand and wildfire activity with preparedness levels” International Journal of Wildland Fire 30(1):30-41. Online: https://www.publish.csiro.au/wf/wf20066.
    11. Higuera PE and Abatzoglou JT. (2020). “Record-setting climate enabled the extraordinary 2020 fire season in the western United States” Global Change Biology 27(1):1–2 Online: https://doi.org/10.1111/gcb.15388

Book Chapter

  1. Ostrander, Madeline. (Upcoming in 2022). At Home on an Unruly Planet: Finding Refuge on a Changed Earth. Henry Holt and Co. ISBN 9781250620514.

White Paper

Dickinson, MB, Abatzoglou JT, Cullen AC, Fillmore S, Fischer P, French N, Hessburg P, Hogland S, Lake F, Linn R, McCaffrey S, Prichard S, Rinkleff PG. Translational Science to Support Wildfire Management for Cultural and Ecological Benefit (2022, prepared for the Joint Fire Science Program, US Forest Service).

Our overall research goal is to understand current and future wildfire characteristics to support fire-related decisions throughout the 21st century in the face of resultant suppression resource scarcity and competition in the US. This project will model future patterns and uncertainty in the simultaneous co-occurrence of megafire events to inform risk management.  

 Research Questions:  

  1. How will climate change alter future patterns of wildfire, particularly co-occurring megafires?  
  2.  What implications does this hold for risk management decisions?   

We are developing statistical models to represent relationships between biogeophysical and human factors (e.g., ignitions, suppression policy, land and fuel management) and firefighting resource demand at geographical scales relevant to firefighting management decision-making. These resource demand and risk management models will be based on wildfire characteristics, climate, weather, and land history covariates. We are evaluating climate change impacts on ignition patterns and on wildfire risk with regional climate model projections from NA-CORDEX, and observations from the gridMET dataset, by looking at fire danger indices in concert with projected spatiotemporal patterns in anthropogenic activities associated with human-caused fires, as well as diagnostics for lightning activity..  


  1. We hypothesize that ignition efficiency will increase further with warming, facilitating increased lightning-ignitions, and consequently increases in simultaneous wildfire events.  
  2. We hypothesize that a positive feedback may occur where fire suppression resources at the national level become strained, reducing the efficacy of managing active fires and new ignitions, and further increasing resource strain and relative burned area.  
  3. We hypothesize that short term fire management decisions (e.g., both fuel management and fire suppression) have significant delayed impacts, and demand innovative scientifically supported decision tools that explicitly account for climate change and the continuing interaction of natural and human systems.

Project Team

Alison Cullen, PI, Daniel J. Evans Endowed Professor of Environmental Policy, Evans School of Public Policy and Governance, University of Washington, Seattle WA. 

John Abatzoglou, Co-PI, Associate Professor, University of California Merced, Merced, CA. 

Melissa Bukovsky, Co-PI, Project Scientist III, National Center for Atmospheric Research, Boulder, CO. 

Sunniva Bloem, Research Assistant, PhD student, Evans School of Public Policy and Governance,  University of Washington, Seattle, WA. 

Alex Dolk, Research Assistant, Evans School of Public Policy and Governance,  University of Washington, Seattle, WA (MPA, 2021; MS, 2021). 

Marie Higinbotham, Research Assistant, Evans School of Public Policy and Governance,  University of Washington, Seattle, WA (MPA expected 2022). 

Reed Humphrey, Research Assistant, PhD student, Evans School of Public Policy and Governance,  University of Washington, Seattle, WA. 

Lee Kessenich, Associate Scientist I, National Center for Atmospheric Research, Boulder, CO. 

Seth McGinnis, Associate Scientist IV, National Center for Atmospheric Research, Boulder, CO. 

Linda Mearns, Senior Scientist, National Center for Atmospheric Research, Boulder, CO. 

Harry Podschwit, Research Assistant, School of Environmental and Forestry Science, University of Washington, Seattle, WA (PhD, 2020). 

Susan Prichard, Senior Research Scientist, School of Environmental and Forest Sciences, University of Washington, Seattle, WA. 

Haley Skinner, Research Assistant, Evans School of Public Policy and Governance, University of Washington, Seattle, WA (MPA expected 2023).

Emily Stephens, Evans School of Public Policy and Governance, University of Washington, Seattle, WA (MPA 2022)

Ashwin Thomas, Research Assistant, PhD student, Environmental Systems,  University of California Merced, Merced, CA. 

Graduate Student Academic Defenses

Dolk, Alex. (MS/MPA 2021). Where There’s Fire, There’s Smoke: Examining Population Exposure to PM2.5 from Prescribed Burning in Northeastern Washington. Concurrent Master’s Thesis. Evans School of Public Policy and Governance, School of Environmental and Forest Sciences, University of Washington, Seattle, WA.

Podschwit, Harry. (PhD, 2021). Accounting for model uncertainties in statistical forecasts of wildfire parameters. Doctoral Dissertation. School of Environmental And Forest Sciences, University of Washington, Seattle, WA.

Stephens, Emily. (MPA, 2022). Winner of the Environmental Policy & Management Research Prize, All Lands, All Plans: Regional and Forest-Level Planning and Coordination in Eastern Washington Forests. Masters Degree Capstone, Evans School of Public Policy and Governance, University of Washington.

Higinbotham, Marie (MPA 2022). Incorporating Equity into Capital Planning and Decision-Making. Masters Degree Capstone. Evans School of Public Policy and Governance, University of Washington, Seattle, WA.


Conference Presentations

“Where there’s fire, there’s smoke: Examining Population Exposure to PM2.5 from Prescribed Burning in Northeastern Washington.” (Ernesto Alvarado, Alison Cullen, Alex Dolk). International Association of Wildland Fire & Climate Conference, Pasadena, CA. May 2022.

“Future changes in Simultaneous Megafire projected by NA-CORDEX” (Melissa Bukovsky) European Geophysical Union. Vienna. May 2022

“Drivers of lightning-ignition efficiency in California forests.” (Ashwin Thomas). International Association of Wildland Fire Conference: Fire & Climate 2022, Pasadena, CA. May 2022.

“Multimodel Uncertainty in Projected Changes of Simultaneous Megafires in the Great Basin Based on NA-CORDEX Regional Climate Simulations.” (Seth McGinnis, Lee Kessenich, Harry Podschwit, Linda Mearns, Melissa Bukovsky, and Alison Cullen). AGU Fall Meeting, New Orleans LA. December 2021.

“Managing Future Fire Risk – an NSF Growing Convergence Research Project.” (Alison Cullen). Society for Risk Analysis 2021 Annual Meeting. December 2021.

“The role of international resource sharing arrangements in wildfire risk management in the face of climate change.” (Sunniva Bloem). Society for Risk Analysis 2021 Annual Meeting. December 2021.

“Symposium: Managing and Reducing the Risk of wildfire through Response and Fuel Treatment.” (Alison Cullen). Society for Risk Analysis 2021 Annual Meeting. December 2021.

“Projected Effects of Climate Change on Simultaneous North American Megafires Based on NA-CORDEX Regional Climate Simulations.”  (Seth McGinnis, Harry Podschwit, Lee Kessenich, Linda Mearns, and Alison Cullen) GC081-07, 2020 Fall Meeting, American Geophysical Union, December 2020 https://agu.confex.com/agu/fm20/meetingapp.cgi/Paper/687152

Managing Future Risk of Increasing Simultaneous Megafires” (Alison Cullen, Harry Podschwit, Linda Mearns, John Abatzoglou, Seth McGinnis, Melissa Bukovsky, Susan Prichard) Society for Risk Analysis 2020 Annual Meeting, December 2020.



NSF Growing Convergence Research Managing Future Risk of Simultaneous Wildfire. Stakeholder Workshop. April 2021.

NSF Growing Convergence Research Managing Future Risk of Simultaneous Wildfire.” Stakeholder Workshop. June 2021.

Convergence Workshop on Simultaneous Fires, Stakeholder Focus Group, Association for Fire Ecology. November 2021.


Webinars, Seminars, and Podcasts

“Burning Issues” Podcast episode on wildfires. (Alison Cullen). Burning Issues. University of Chicago. June 2022.

“Climate change and the risk of Western fire activity.” (John Abatzoglou). IBHS Disaster Dynamics Academy, March 2022.

“Climate Change and Simultaneous Megafires in the Western US.” (Seth McGinnis). Presentation, CGD Seminar, Boulder CO, 1 March 2022. Online: https://www.youtube.com/watch?v=tt9HnbMjv9o.

“Climate change adaptation for western forests, watersheds, and communities.” (Susan Prichard). FEMA Region 10 Regional Interagency Steering Committee (RISC) Meeting. March 2022.

“Climate change impacts on demand for emergency resources.” (Reed Humphrey). FEMA Region 10 Regional Interagency Steering Committee (RISC) Meeting. March 2022.

“Western wildfires – adapting to a future with more fire.” (Susan Prichard). University of Washington Botanical Gardens, Seattle, WA, March 2, 2022.

“Common questions about adaptive forest management.” (Susan Prichard). Guest lecture, Environmental and Resource Management 101: Forests and Society. February 2022.

“Managing Future Risk of Increasing Simultaneous Megafires” (Melissa Bukovsky), National Center for Atmospheric Research, Research Applications Lab, December 2021.

“Landscape fuel treatments and wildland fire management strategies within recent large fire events.” (Susan Prichard, N Povak, R Lemons, V Griffey). Northwest Fire Science Consortium Webinar. November 18, 2021.

“Climate driven fire hazards: knowledge and limitations.” (John Abatzoglou). Bureau of Meteorology Annual Conference, Melbourne Australia (remote), November 2021.

“Common questions about adaptive forest management.” (Susan Prichard). Society of American Foresters, Washington Chapter. Webinar, November 11, 2021.

“Wildfire Smoke Engagement Workshop: Fire Ecology.” (Susan Prichard). SNAPP wildfire smoke engagement workshop Okanogan, WA, November 8, 2021.

“Common questions about adaptive forest management.” (Susan Prichard, P Hessburg, K Hagmann). UW School of Environmental and Forest Sciences Fall Seminar Series, October 28, 2021.

“The rise of fire in the Western United States: drives, impacts, and solutions” (John Abatzoglou). National Academies of Engineers, Sep 2021

“Climate Challenges for Wildland Fire Management” (John Abatzoglou).  University of California Wildfire Symposium Series, Aug 2021

Colorado Congressional Forum on Wildfire and Extreme Climate, Rep. Joe Neguse, Linda Mearns,  discussant, Highlands Institute Boulder,  August 2021.

“Compound Extremes Drive the Western Oregon Wildfires of September 2020” (John Abatzoglou) Pacific Northwest Drought Early Warning System webinar series, June 2021.

“Wildfire Risk Management and Decision Analytic Approaches” (Alison Cullen) Faculty Research Introduction, Evans School, University of Washington, Seattle, WA, March 19, 2021.

“Climate Change Impacts in Colorado” (Melissa Bukovsky) Protect Our Winters, Colorado Chapter.  January 2021.

“Climate information for fire management in SW Forests” (John  Abatzoglou)  Fire Science & Management in an Uncertain Future webinar series, December 2020.

“Wildfires and Climate Change in the Pacific Northwest.” (Susan Prichard) Association of Women in Science – Seattle Chapter. December 2020.

“Climate change and the risk of Western fire activity, Wildfires, Litigation, and What Science Can Tell Us” (John Abatzoglou) National Judicial College webinar, October 2020.

“Fuel Treatments and Megafires: lessons from the large fires in north-central WA” (Susan Prichard) University of California Fire Science Seminar Series. October 2020.

“Why are wildfires increasing in the Pacific Northwest?” (Susan Prichard) Washington on Fire Seminar, Washington State University Graduate and Professional Student Science Policy Initiative. October 2020.

“Wildfire Risk Management: Future Trends and Impact on Decision Making” (Alison Cullen) Cascadia Wildfire and Urban Smoke Webinar, Seattle, WA, 2020.

Climate projections and simultaneous wildfires

  • Unless we take steps to address the situation – most of the Western US is projected to see numbers of simultaneous, 1000+ acre fires that historically occurred once every ten years happening once every five years – or even more frequently (McGinnis et al., 2022).
  • In the US, the median number of large fires (i.e., greater than the historic 75th percentile) occurring simultaneously from July to September was about 3 times higher in 2010-2019 than it was in 1984-1993 (Podschwit and Cullen, 2020; Cullen et al., 2022).
  • During the month of peak fire intensity in the US, the number of large fires (i.e., greater than the historic 75th percentile) occurring simultaneously was twice as high in 2010-2019 as it was in 1984-1993 (Podschwit and Cullen, 2020; Cullen et al, 2022).
  • In Alaska, the average number of large fires (i.e., greater than the historic 75th percentile) during peak fire activity months approximately doubled in 2002-2019 compared to 1984-2001. In the Northwest US, the average number of large fires during peak fire activity months increased almost 30% between these two periods (Cullen et al, 2022).
  • In the Northern Rockies region, conditions of more than 35 simultaneous wildfires 1000+ acres in size, which historically occurred once per decade, are projected to occur on average every two years by the end of this century (McGinnis et al., 2022).

Preparing for future wildfire seasons – resource preparedness

  • As periods of co-occurring wildfire increasingly overlap across US regions, competition for suppression resources has been increasing, a trend which is expected to continue and intensify (Podschwit and Cullen, 2020; Cullen et al., 2020).
  • The current capacity, in terms of hiring, staffing and preparing, of fire operations organizations is insufficient for responding effectively in the coming decades given the projected number and intensity of impactful fires (Podschwit and Cullen, 2020; Cullen et al., 2020).
  • In the Western US, the season during which wildfires compete for suppression resources is projected to begin 2-4 weeks earlier and end 2 weeks later in 2040-2070 than it did during 1980-2010. Overall, wildfire season length will increase by 4-6 weeks (McGinnis et al, 2022).
  • In 2021, the US national preparedness level reached its maximum (PL=5) at the earliest point in the year ever recorded, 14 July, indicating that suppression resources were already fully committed in response to simultaneous active fires at that date (Abatzoglou et al., 2021).
  • With increasing intensity of wildfire seasons, national resources will be subject to ever higher levels of competition, necessitating increased reliance on international resource-sharing relationships (Bloem et al., 2022).

Proactive Forest Management (Mitigating fire risk under climate change)

  • Fire management in the US must become proactive rather than reactive in the face of the lengthening of the simultaneous wildfire season by several weeks, alongside a notable increase in the risk of extreme fire weather.
  • In recent decades, increased area burned by western wildfires has been associated with uncharacteristically large patches of high-severity, stand-replacing fire (Parks and Abatzoglou 2020, Hagmann et al. 2021).
  • Because high-severity fire events can be catalysts for vegetation change, trends in large wildfires and burn severity have implications for rapid ecosystem shifts and declines in valued resources (Kemp et al. 2019, Stevens-Rumann and Morgan 2019, Coop et al. 2020).
  • Combining western science and Indigenous knowledge systems is foundational to intentionally restoring and adapting western forest ecosystems (Kimmerer and Lake 2001, Lake et al. 2017, Roos et al. 2021).” (Prichard et al. 2021)
  • Adaptive management is a learning-by-doing method of responding to ecosystem changes, informed by effectiveness monitoring (Lyons et al. 2008, Larson et al. 2013b).
  • Restoring open forest structure and composition, favoring larger tree sizes, and reducing surface fuels can effectively mitigate future wildfire severity in dry, fire-prone forests, including oak and pine woodland and semi-arid mixed conifer forests of the western US.
  • Despite calls to restore fire as a cultural and ecological process (e.g., The U.S. National Wildland Fire Cohesive Strategy), the dominant approach to wildfire management continues to be aggressive suppression. (Prichard et al. 2021)
  • Under active fire suppression, forest infilling and fuel accumulation predisposes forests to high-severity fire when fire inevitably returns to the locations where it has been previously suppressed (North et al. 2015b)



Co-Investigator Susan Prichard briefs President Biden to discuss the climate crisis and his new Executive Order strengthening America’s forests, boosting wildfire resilience, and combating global deforestation.

The Return of Intentional Forest Fires: Scientists look to Indigenous practices. (Bioscience). 17 March 2022. https://doi.org/10.1093/biosci/biac016

Western US’s Worst Drought in 1,200 Years Brings Year-Long Fire Season. 13 March 2022 (Truthout) https://truthout.org/articles/western-uss-worst-drought-in-1200-years-brings-year-long-fire-season/.

‘Another reason to lose sleep’: California fires are growing more intense at night. (The Sacramento Bee). 25 February 2022. https://www.sacbee.com/news/california/fires/article258701563.html.

‘In wildfire ‘pivot’ experts question federal focus.’ (Roll Call). 28 January 2022. https://rollcall.com/2022/01/28/in-wildfire-pivot-experts-question-federal-focus/.

‘2021: The Year in Climate Change.’ (Sierra). 4 December 2021. https://www.sierraclub.org/sierra/2021-year-climate-change.

‘Why fire experts are hopeful.’(High Country News). 1 November 2021.  https://www.hcn.org/issues/53.11/north-wildfire-why-fire-experts-are-hopeful.

For Forest Blazes Grown Wilder, an Alternative: The ‘Good Fire.’ (Undark). 25 October 2021. https://undark.org/2021/10/25/for-forest-fires-grown-wilder-an-alternative-the-good-fire/.

Local fire ecologist addresses forest management debate (Methow Valley News) 1 September 2021. https://methowvalleynews.com/2021/09/01/local-fire-ecologist-addresses-forest-management-debate/

Experts call for expanded wildfire prevention tactics as fire seasons become more extreme (Yakima Herald-Republic) 7 September 2021. https://www.yakimaherald.com/news/local/experts-call-for-expanded-wildfire-prevention-tactics-as-fire-seasons-become-more-extreme/article_5ff9f141-1260-5bc9-9ad7-e0b35fe4aca3.html

An Update on This Year’s Wildfires: It’s Bad! (The Stranger) 26 August 2021. https://www.thestranger.com/slog/2021/08/26/60791981/how-do-we-stop-washington-wildfires-just-set-more-fires

Wildfires grow worldwide as climate sizzles (Associated Press), 19 Aug. 2021. https://apnews.com/article/us-news-fires-climate-environment-and-nature-california-7f186fbe7fade35c3a59cc53d66ff626

Forest management not so clear cut (Street Roots) 17 August 2021. https://www.streetroots.org/news/2021/08/17/forest-management-not-so-clear-cut

Wildfires: How are they linked to climate change? (BBC) 11 August 2021. https://www.bbc.com/news/58159451

What The UN’s Latest Climate Report Means For Colorado (Colorado Public Radio), 9 Aug. 2021. https://www.cpr.org/2021/08/09/un-climate-report-what-it-means-for-colorado

How years of fighting every wildfire helped fuel the Western megafires of today (The Conversation) 2 August 2021. https://theconversation.com/how-years-of-fighting-every-wildfire-helped-fuel-the-western-megafires-of-today-163165

State of the science on western wildfires, forests and climate change (UW News) 2 August 2021. https://www.washington.edu/news/2021/08/02/new-report-state-of-the-science-on-western-wildfires-forests-and-climate-change/

US heatwave: Could US and Canada see the worst wildfires yet? (Reality Check Team, BBC) 13 July 2021. https://www.bbc.com/news/57770728

States spend big as water levels fall, raising risks for catastrophic fires (The Hill) 29 June 2021. https://thehill.com/policy/equilibrium-sustainability/560733-states-spend-big-as-water-levels-fall-raising-risks-for

All software and data products generated by this project are publicly available. The code and documentation that we have developed for calculating fire indices in support of climate projections is publicly available on GitHub: https://github.com/NCAR/fire-indices. Visualizations appear in both published papers and above on this page.