Visualizing Pyroclimotology

Benjamin Hatchett , T. Todd Lindley, John Abatzoglou, Ansley Baring, Alexander Gershunov, Kristen Guirguis, Robert Munroe, Nick J. Nauslar, Eli Orland, Alan M. Rhoades, Karen C. Short, Rochelle P. Worsnop

Background: Wildland fire activity often demonstrates distinct seasonality adhering to the alignment of climatologically favorable fuels, weather, and ignitions. Improved characterization of conditions that increase fire ignition probabilities, extreme fire behavior, and beneficial fire potential would enhance our understanding of fire regimes and provide insight for future wildland fire management. 

Methods: We apply a commonly-utilized tool--the climograph--to visually communicate historical wildland fire activity by demonstrating fire seasonality, interannual variability, and past individual fire events at daily resolution using satellite observations in three distinct case study areas. We apply the analysis to three units of analysis (50 states, 128 pyromes, and 122 National Weather Service County Warning Areas) to evaluate cumulative FRP during calendar year 2026 (through 20 July) and place this year into a pyroclimotological perspective.

Results: Detection counts and cumulative fire radiative power (FRP) in the resulting “pyroclimographs” provide first-order indicators of fire activity seasonality (i.e., wildfires or prescribed burns) and when anomalous activity occurs out-of-season. In coastal Southern California, we show how pyroclimographs vary as the region of interest shifts and how their interpretation can be complemented by including climatological interpretations of additional fire environment data. Pyroclimographs help characterize the fraction of FRP contributed from few or many events, i.e., how many days contribute 50% or 90% of total FRP since satellite observations began. The 1 January–20 July 2026 pyroclimographs indicate widespread record-to-near record satellite-era fire activity by mid-2026 across the United States.

Conclusions: Pyroclimographs may aid identification of environmental factors associated with past fire occurrence or provide understanding of typical timing of smoke impacts and their sources, all of which can be interpreted in the context of evolving real-time conditions and used for longer-term planning. Given the current ubiquity as well as current and projected increase of wildland fire in many regions, we recommend considering pyroclimographs as a visualization tool supporting varied applications where information regarding wildland fire seasonality and characteristics will benefit users.