AVO reported that during 7-8 September clear-weather satellite views of Cleveland showed no thermal anomalies or recent deposits on the flanks. The Volcano Alert Level and the Aviation Color Code were lowered to Unassigned. On 11 September, a thermal anomaly was observed in satellite imagery. The next day a possible ash plume seen in satellite imagery rose to the estimated altitude of 7.6 km (25,000 ft) a.s.l. and drifted E. The Volcano Alert Level and the Aviation Color Code were again raised to Advisory and Yellow, respectively. A thermal anomaly was again visible during 13-14 September.

Geological Summary. The beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano. Joined to the rest of Chuginadak Island by a low isthmus, Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano. Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998). In 1944 it produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.

Source: US Geological Survey Alaska Volcano Observatory (AVO)