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Thursday, September 22, 2011 12:27 PM AKDT (Thursday, September 22, 2011 20:27 UTC)

52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Clouds have prevented satellite views of Cleveland during the last 24 hours; AVO is unable to verify if eruption of a lava at Cleveland is continuing. As of September 20, 2011 satellite imagery showed a 165 m (541 ft) in diameter lava dome in the summit crater. AVO has received no other reports of activity at Cleveland.

A growing lava dome in the crater increases the possibility of an explosive event, but does not necessarily indicate that one will occur. It is possible that explosions from the summit crater vent could produce ash clouds that may exceed 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours. If lava dome growth continues, lava may overflow the crater rim to produce a lava flow and/or collapse to produce pyroclastic flows. Sudden collapse of the effusing lava could result in the generation of a volcanic ash cloud.

Without a real-time seismic network on the volcano, AVO is unable to track local earthquake activity related to volcanic unrest, provide forecasts of eruptive activity, or confirmation of explosive, ash-producing events. AVO will continue to monitor the volcano using multiple sources of satellite data.

Chris Waythomas, Acting Scientist-in-Charge, USGS (907) 786-7497

Scott Stihler, Acting Coordinating Scientist, UAF (907) 474-5450

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.