|Start:||August 17, 1989 ||Observed|
|Tephra plume: ||
|Central eruption: ||
|MaxVEI: ||1 ||
From Reeder (1992): "At 1430 on August 17, 1989, Evan Klett of the U.S. Fish and Wildlife observed from the Reeve Aleutian Airways Inc. 727 Boeing Jet, flying from Shemay Island to Adak Island, a grayish to black tephra plume that was about 700 m above the northern near summit crater of Gareloi volcano. The plume covered the top of the 400 m by 260 m near summit crater, which prevented Evan from seeing into the crater. The tephra plume was definitely originating from the summit crater."