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Full-Text Articles in Geography
Lightning-Ignited Wildfires In The Western United States: Ignition Precipitation And Associated Environmental Conditions, Dmitri Alexander Kalashnikov, John T. Abatzoglou, Paul Loikith, Nicholas J. Nauslar, Yianna Sotirios Bekris, Deepti Singh
Lightning-Ignited Wildfires In The Western United States: Ignition Precipitation And Associated Environmental Conditions, Dmitri Alexander Kalashnikov, John T. Abatzoglou, Paul Loikith, Nicholas J. Nauslar, Yianna Sotirios Bekris, Deepti Singh
Geography Faculty Publications and Presentations
Cloud-to-ground lightning with minimal rainfall (“dry” lightning) is a major wildfire ignition source in the western United States (WUS). Although dry lightning is commonly defined as occurring with <2.5 mm of daily-accumulated precipitation, a rigorous quantification of precipitation amounts concurrent with lightning-ignited wildfires (LIWs) is lacking. We combine wildfire, lightning and precipitation data sets to quantify these ignition precipitation amounts across ecoprovinces of the WUS. The median precipitation for all LIWs is 2.8 mm but varies with vegetation and fire characteristics. “Holdover” fires not detected until 2–5 days following ignition occur with significantly higher precipitation (5.1 mm) compared to fires detected promptly after ignition (2.5 mm), and with cooler and wetter environmental conditions. Further, there is substantial variation in precipitation associated with promptly-detected (1.7–4.6 mm) and holdover (3.0–7.7 mm) fires across ecoprovinces. Consequently, the widely-used 2.5 mm threshold does not fully capture lightning ignition risk and incorporating ecoprovince-specific precipitation amounts would better inform WUS wildfire prediction and management.
Spatial Analysis Of Streamflow Trends In Burned Watersheds Across The Western Contiguous United States, Heejun Chang, Will B. Long
Spatial Analysis Of Streamflow Trends In Burned Watersheds Across The Western Contiguous United States, Heejun Chang, Will B. Long
Geography Faculty Publications and Presentations
Despite increasing magnitude and frequency of wildfire, understanding hydrological processes contributing to changes in streamflow is not well examined for the entire western contiguous United States (WCONUS). This study provides insight into whether considering spatially varying watershed characteristics, including burn severity patterns, can better explain streamflow trends at broad spatial and temporal scales. Standard geographically weighted regression (GWR) and multi-scalar (MS) GWR were benchmarked against ordinary least squares (OLS) regression to determine if spatially varying coefficients could better explain spatially varying patterns and processes of peak flow, low flow, center timing of flow, and flashiness trends in burned watersheds. In …
Reduced Fire Severity Offers Near-Term Buffer To Climate-Driven Declines In Conifer Resilience Across The Western United States, Kimberly T. Davis, Marcos D. Robles, Kerry B. Kemp, Teresa Chapman, Philip E. Higuera, Kerry L. Metlen, Jamie L. Peeler, Andres Holz, Multiple Additional Authors
Reduced Fire Severity Offers Near-Term Buffer To Climate-Driven Declines In Conifer Resilience Across The Western United States, Kimberly T. Davis, Marcos D. Robles, Kerry B. Kemp, Teresa Chapman, Philip E. Higuera, Kerry L. Metlen, Jamie L. Peeler, Andres Holz, Multiple Additional Authors
Geography Faculty Publications and Presentations
Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, the relative importance of and interactions between these drivers of forest change remain unresolved, particularly over upcoming decades. Here, we assess how the interactive impacts of changing climate and wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset of postfire conifer regeneration from 10,230 field plots. Our findings highlight declining regeneration capacity across the West over the past four decades for the eight dominant conifer species studied. Postfire regeneration is sensitive to high-severity fire, which limits …