Plume height for each of the 70 explosions at Bogoslof, shown as red and black bars, is determined by satellite. Red bars indicate plumes that generated globally detected lightning. Dashed bars indicate unknown plume height, shown at an arbitrary altitude of 2 kilometers. Shading indicates atmospheric temperatures over Bogoslof. The darker shading shows the altitude at which the temperature was 32 ºF (0 ºC). The lighter shading shows the atmospheric freezing level of water, —4 ºF (—20 ºC). Stars indicate two plumes that generated volcanic lightning, but did not clearly rise above the atmospheric freezing level of water. However, Van Eaton and colleagues point out that both may have been higher than suggested, based on photographic evidence and measurements of volcanic gases high in the atmosphere. Credit: Van Eaton et al., 2020