The smoke from wildfires that ravaged North America in mid-2017 blotted out as much sunlight as a moderate volcanic eruption.
The smoke was particularly thick in August 2017 as fires burned in northwestern Canada and the United States. Laser instruments at the Haute-Provence Observatory near the village of Saint Michel l’Observatoire, France, tracked the layers of smoke particles as they drifted overhead, and the CALIPSO satellite confirmed the measurements from orbit. A team led by Sergey Khaykin at the Institute Pierre-Simon Laplace in Guyancourt, France, studied these data and report that the smoke blocked more sunlight than the 2009 eruption of Russia’s Sarychev Peak. That eruption measured four out of eight on a scale used to rate the explosive power of volcanoes.
Future studies could provide insight into the mechanisms that allowed the smoke to travel long distances in the stratosphere, the authors say.