|Start:||August 24, 2006 ||Observed|
|Stop:||October 28, 2006 ||Observed|
|Tephra plume: ||
|Duration: ||Intermittent |
|ColHeight: ||3048 m |
|MaxVEI: ||3 |
From Neal and others (2009): "On August 24, AVO received notice from NWS that a ship had reported an ash eruption from Cleveland volcano. Days later, AVO received video footage from the crew of this fishing vessel showing a definite ash plume reaching about 3 km (~10,000 ft) ASL [see fig. 42 in original text]. Importantly, neither a broadband regional network seismic station in Nikolski [see fig. 1 in original text; M. West, UAFGI, written commun., 2006) nor any time-correlative satellite imagery showed evidence of this eruption. On September 7, after reviewing video footage of the August 24 event and noting an intermittently present thermal anomaly at the volcano, AVO raised the Level of Concern Color Code to YELLOW.
"AVO was alerted by NWS of another Cleveland eruption on October 28 after a pilot report to the Anchorage Air Traffic Control Center. The pilot of a jetliner indicated an initial cloud over the volcano reaching their flight level of 36,000 ft (11,000 m) ASL, and a drifting cloud moving east-northeast at a lower level of 30,000 ft (9,100 m) ASL. Satellite-derived cloud top temperature estimates placed the plume much lower. Utilizing the new warning scheme adopted by United States Volcano Observatories in October, AVO declared Aviation Color Code ORANGE and Volcanic Activity Alert Level WATCH for Cleveland about 2 hours after receipt of the pilot report, and reverted to YELLOW/ADVISORY on October 30 after no indications of further activity. On clear days under optimal satellite viewing conditions, a weak thermal anomaly was detected in the vicinity of the summit crater at Cleveland into November [see fig. 43 in original text]."