An integrated wildfire event database for improved fire science research for the continental United States, 1992–2021

A newly developed wildfire event database covering the continental United States from 1992 through 2021 produces higher estimates of total burned area in every US region, as well as a greater number of extreme wildfires and more burned area associated with events larger than 5,000 hectares. The result emerges from an effort to integrate and reconcile records in three existing national datasets, identify fires missing from those sources and address ambiguities in how complex events, merged fires and duplicate records were represented. The preprint, written by Eric S. Kasischke and Nancy H. French of the Michigan Tech Research Institute, is under review in Earth System Science Data.

The underlying datasets have provided a foundation for numerous wildfire studies in the continental United States over the past two decades, but discrepancies among their records can complicate efforts to determine how many individual fires occurred and how large they were. Kasischke and French began by mining information from the three national sources, then combined it with regional reports, regional datasets and information found through searches of the world wide web. Fires not represented in the original national datasets were added when the broader search identified them as distinct events. The resulting inventory is intended to improve the information available for quantifying annual area burned and changes in extreme wildfire activity at different spatial scales.

Much of the work focused on records whose descriptions or measurements did not align. The researchers developed specific approaches for cases in which the same fire appeared with substantially different reported sizes, fires were labeled as complexes, several fires were contained within a larger event, smaller events merged into a larger one, events later joined, sizes were reported incorrectly or records were duplicated. These are consequential distinctions for event-based inventories because the treatment of a complex incident affects both the number assigned to a fire and the area attributed to it. The database seeks to reconcile these cases before researchers aggregate individual records into annual, regional or national totals.

Calculations using the integrated database increase total burned area for all United States regions. They also yield more extreme wildfires—defined in the study’s short summary as events larger than 5,000 hectares—and a larger area burned by events above that threshold. The authors present these results as differences between measurements generated from the new event database and those obtained from the records currently used by the fire-science community, rather than as projections of future wildfire activity. The comparison illustrates how the number, size and classification of recorded events can shape estimates of burned area and the prevalence of extreme fires across the full 1992–2021 inventory.

The work is a preprint and has not yet completed the journal’s review process. The supplied record states that the manuscript was received on 23 August 2026 and entered discussion on 21 October 2026, with a supplement also available from the preprint record. Its geographic scope is the continental United States, and its temporal scope is the three decades from 1992 to 2021. The database also depends on the quality and consistency of the national, regional and web-based information used to construct and reconcile it. Within those limits, the study’s central contribution is methodological: it provides a harmonized inventory of individual wildfire events designed to reduce uncertainties in the counts, areas and extreme-event measurements used in fire-science research.

Subject of Research: An integrated event database for measuring wildfires across the continental United States from 1992 to 2021

Article Title: An integrated wildfire event database for improved fire science research for the continental United States, 1992–2021

Article References: Kasischke, E. S., & French, N. H. (2026). An integrated wildfire event database for improved fire science research for the continental United States, 1992–2021. https://doi.org/10.5194/essd-2026-660

Image Credits: AI Generated

DOI: 10.5194/essd-2026-660

Keywords: wildfire database, burned area, extreme wildfires, United States, fire records, data reconciliation, event classification, 1992–2021, wildfire science, preprint, integrated, wildfire