In 2023, the lidar team at Garmisch-Partenkirchen (Germany) celebrated its 50th year of aerosol profiling. The highlight of these activities has been the lidar measurements of stratospheric aerosol carried out since 1976. The observations since 2017 are characterized by severe smoke from several big fires in North America and Siberia and three volcanic eruptions. The sudden increase in the frequency of such strong fire events is difficult to understand.

Forest fires in British Columbia in August 2017 caused an unusual phenomonon: smoke and gases from the fires rose quickly to a height of 10 km. From there, the pollution continued to rise more slowly for many weeks, travelling around the world as it did so. In this paper, we describe how we used data from a satellite instrument to observe this polluted volume of air. The satellite has now been working for 16 years but has observed only three events of this type.