Alaska's Cleveland Volcano sends cloud of ash across Aleutians
An eruption at Cleveland Volcano in Alaska's Aleutian Islands sent a cloud of ash 15,000 feet into the air Thursday, prompting a warning to aviation traffic. But the cloud had mostly dissipated by Friday morning.
The smoking crater remained on "watch" status, however, with officials at the Alaska Volcano Observatory watching for the possibility of another eruption. A lava dome has been rising in the 5,676-foot peak and sending off warning signs since July.
"There is concern that Cleveland is a very, very active volcano. It has been very active over the past year, as well as over the past 10 years, so we are concerned that this type of activity could be repeated," John Power, scientist in charge for the U.S. Geological Survey at the observatory, told the Los Angeles Times.
Thursday's eruption and the drifting cloud of ash that followed it presented a threat to local aviation traffic in the Aleutians, which are home to one of the nation's busiest fishing ports, but the cloud did not reach high enough to imperil major commercial jet traffic, which typically flies above 25,000 feet.
Cleveland's most significant recent eruption, in 2001, sent ash clouds soaring up to 39,000 feet, along with a rubbly lava flow and hot avalanche that reached the sea, according to the observatory's report on its website.
"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," the report warned.
Cleveland has historically been hard to monitor; it lies on uninhabited Chuginadak Island more than 900 miles southwest of Anchorage, and scientists have no ground instrumentation, such as seismometers or global positioning system equipment, to gather detailed data.
The nearest community, Nikolski, about 45 miles to the east with a permanent resident population of 18, was not considered threatened.
Power said USGS officials are waiting to gather additional satellite imagery before officially downgrading the volcano's current "orange-watch" status.
-- Kim Murphy in Seattle
Photo: Cleveland Volcano is too remote to photograph regularly, but scientists from the National Oceanic and Atmospheric Administration flew by and photographed an eruption in August. Credit: Kym Yano / NOAA