According to the Alaska Volcano Observatory, a single explosive event sent an ash cloud up to 15,000 feet from Cleveland Volcano. Satellite images from December 29 reveal the ash cloud has detached and is drifting east/southeast from the volcano.
Based on the presence of an ash cloud, AVO has raised the aviation color code at Cleveland Volcano to ORANGE and alert level WATCH.
Satellite data indicate that this is a single explosion event, however, more sudden explosions producing ash could occur with plumes exceeding 20,000 feet above sea level. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes. There is no real-time seismic monitoring network at Cleveland.
Cleveland Volcano forms the western half of Chuginadak Island in the east central Aleutians. It is located about 45 miles west of the community of Nikolski.
Additional information on Cleveland Volcano and the current activity may be found at http://www.avo.alaska.edu/activity/Cleveland.php.