Notable impact of wildfires in the western United States on weather hazards in the central United States

Abstract

Increased wildfire events constitute a significant threat to life and property in the United States. Wildfire impact on severe storms and weather hazards is another pathway that threatens society, and our understanding of which is very limited. Here, we use unique modeling developments to explore the effects of wildfires in the western US (mainly California and Oregon) on precipitation and hail in the central US. We find that the western US wildfires notably increase the occurrences of heavy precipitation rates by 38% and significant severe hail (≥2 in.) by 34% in the central United States. Both heat and aerosols from wildfires play an important role. By enhancing surface high pressure and increasing westerly and southwesterly winds, wildfires in the western United States produce ( 1 ) stronger moisture and aerosol transport to the central United States and ( 2 ) larger wind shear and storm-relative helicity in the central United States. Both the meteorological environment more conducive to severe convective storms and increased aerosols contribute to the enhancements of heavy precipitation rates and large hail. Moreover, the local wildfires in the central US also enhance the severity of storms, but their impact is notably smaller than the impact of remote wildfires in California and Oregon because of the lessened severity of the local wildfires. As wildfires are projected to be more frequent and severe in a warmer climate, the influence of wildfires on severe weather in downwind regions may become increasingly important.

Impact of Solar Geoengineering on Wildfires in the 21st Century in CESM2/WACCM6

“…For example, fires degrade air quality and human health as many of the emitted gases and aerosols from fires are primary pollutants or precursors to secondary chemically-produced pollutants (Wiedinmyer et al, 2006;van der Werf et al, 2006). Fires also alter regional dynamics and weather through changing surface heat and water vapor fluxes, convection, clouds, and precipitation (e.g., Bowman et al, 2009;Coen et al, 2013, Zhang et al, 2022.…”

Interannual variability and trends of summertime PM2.5-based air quality in the Intermountain West

“…Recent advances in Earth system models and decadal climate prediction approaches offer the potential to forecast wildfires on multi-year timescales (Chikamoto et al 2017(Chikamoto et al , 2020. Additionally, recent progress in regional and global atmospheric models, coupled with chemistry components, allows for the realistic simulation of fire events and associated aerosol transport (Ye et al 2021, Zhang et al 2022. However, the spatiotemporal coverage of air quality observations is currently insufficient to isolate the impact of long-term climate change from interannual climate variability.…”

Case study evaluation of size-resolved molecular composition and phase state of carbonaceous particles in wildfire influenced smoke from the Pacific Northwest

“…In general, the importance of understanding wildfire-derived particles is rapidly growing alongside the escalating climate crisis. 75 To exemplify the significance of this topic, a recent study by Damany-Pearce et al showcased that the largest stratospheric warming event since the eruption of Mount Pinatubo in 1991 was due to the 2019–2020 eastern Australia wildfires. 76 Therefore, as the contribution of wildfire particles to the total atmospheric particle load increases, so do the implications for proper characterization and subsequent incorporation of wildfire particles in climactic models.…”