Intense forest fires in western North America during August 2017 caused smoke plumes that reached deep into the stratosphere. While this phenomenon has been observed previously, Bourassa et al.  report that this particular event caused increases in stratospheric aerosols at higher altitudes (up to 23 kilometers) with greater magnitude than observed over the past 40 years. The effects covered most of the Northern Hemisphere and persisted for more than 5 months, rivaling the stratospheric influence of recent moderate volcanic eruptions. Ongoing research is aimed at understanding the chemical and radiative impacts of such far-reaching forest fire events.
Citation: Bourassa, A. E., Rieger, L. A., Zawada, D. J., Khaykin, S., Thomason, L. W., & Degenstein, D. A. . Satellite limb observations of unprecedented forest fire aerosol in the stratosphere. Journal of Geophysical Research: Atmospheres, 124, 9510– 9519. https://doi.org/10.1029/2019JD030607
—William J. Randel, Editor, JGR: Atmospheres