On June 12th, astronauts onboard the International Space Station watched in amazement as Russia's Sarychev Peak volcano erupted directly beneath their spacecraft. The rare photo they took shows the enormous sulfur dioxide plume from the eruption. Researchers have pointed out a few phenomena that caught their eye in the picture.
(1) The volcano erupted with such force, the plume actually punched through the atmosphere. Note how clouds around the volcano have parted in a circular ring--that is a result of a shock wave produced by the upward blast. (2) The plume is a mixture of brown ash and white steam. A "dirty thunderstorm" complete with lightning could be in progress within the roiling cloud. (3) The smooth white bubble on top of the plume is probably a mass of water condensing from air shoved upward by the rising ash column.
This plume is now circumnavigating the globe at northern latitudes, producing spectacular sunsets for international air travelers. Volcanic sunsets have been seen in Oregon this past weekend with the clear blue sky turning purple with several sets of delicate wavelike clouds appearing. The high wavelike clouds are made of ash and sulfuring particles from the volcano. Purple is one of the telltale colors of a volcanic sunset. Fine volcanic aerosols in the stratosphere scatter blue light which, when mixed with ordinary sunset red, produces a violet hue. Unfortunately we won’t have clear weather through the Twin Tiers this week, but if we did we could see some pretty sunsets.