Alaska Volcano Observatory

Closer view of the nearly 5700-ft-summit of Cleveland volcano on July 27, 2007. Water vapor and other gases billow from the steep-walled crater, approximately 150 m (490 ft) across. Prominent yellow-staining reflects precipitation of native sulfur from ongoing release of volcanic gas. Note the mantle of grey debris and blocks along the crater rim, probably produced during intermittent explosive activity at Cleveland over the past few weeks. Two days before this photo was taken, ASTER satellite data indicated temperatures as high as 359 C (678 F) in the summit region. Thermal anomalies have been seen intermittently by satellite since early June when this recent period of elevated activity apparently began.