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| Earth on Nov 12, 2012

When Alaska’s Cleveland Volcano puffs out ash

Scientists keep an eye on this volcano, which can be hazardous to aircraft. When it releases ash, its “aviation code color” may be raised from yellow to orange.

Mount Cleveland – otherwise known as Cleveland Volcano – is a remote and uninhabited island in the Aleutian Island chain extending from Alaska. Although it’s remote, scientists keep an eye on this volcano because, when it spews out ash, it can create a hazard for aircraft. For example, on November 10, 2012, Earth-orbiting satellites detected a small ash cloud from Mount Cleveland. The ash was drifting slowly toward the east-northeast from the volcano’s summit. As a result, the aviation code color for Cleveland Volcano was raised from yellow to orange. The U.S. Geological Survey (USGS) said in a release:

Sudden explosions of blocks and ash remain possible with little or no warning. The previous confirmed explosion occurred on August 20 [2012]. Ash clouds, if produced, could exceed 20,000 feet above sea level

Mount Cleveland is a volcano on the Islands of the Four Mountains in Alaska’s Aleutian Island chain. It’s near the center of this image, which was taken August 2010 by NASA’s Terra satellite. You can see red vegetation (false colour), a white snow-covered peak, a light plume of gas and ash, and dark lanes where ash and debris fell or flowed. Image via NASA.

This volcano – located about 75 kilometers (45 miles) west of the community of Nikolski, and 1,500 kilometers (940 miles) southwest of Anchorage – is one of the most active in this region. It has erupted at least 21 times in the last 230 years, with its only known direct fatality occurring in 1944. Most recently, Mount Cleveland has erupted three times in 2009, twice in 2010, and once in 2011. Scientists observed the most recent minor ash emission in August 2012, prior to the November 10 event.

Location of Cleveland volcano and other Aleutian volcanoes with respect to nearby cities and towns. Image via Alaska Volcano Observatory / Alaska Division of Geological & Geophysical Surveys.

Why monitor this remote volcano? Flights over the North Pacific often sweep over this region of the world. Volcanic ash released from volcanic eruptions can damage sensitive electronic avionic equipment and sensors.

Cleveland Volcano’s remoteness makes it tough to monitor, and the Alaska Volcano Observatory relies heavily on satellites for monitoring. When announcing the November 10 release of ash, USGS said:

If a large ash-producing event occurs, nearby seismic, infrasound, or volcanic lightning networks should alert AVO [Alaska Volcano Observatory] staff quickly. However, for some events, a delay of several hours is possible. There is no real-time seismic monitoring network on Mount Cleveland and AVO is unable to track activity in real time.

So the potential hazard to aircraft is real.

Astronaut photo of ash cloud from Mount Cleveland in 2006. This photo was taken from the International Space Station.

Bottom line: Earth-orbiting satellites detected a small ash cloud from Mount Cleveland – also known as Cleveland Volcano – on November 10, 2012. This is one of the most active volcanoes in the Aleutian Island chain extending from Alaska. Scientists keep an eye on this volcano, because it can be hazardous to aircraft. When it released ash on November 10, the aviation code color for Cleveland Volcano was raised from yellow to orange.

Look here for current alert levels and more info about Cleveland Volcano

Satellite radar image, showing 200-meter-wide summit of Cleveland Volcano on February 10, 2012. You can see a small lava dome within the summit crater. Image via Alaska Volcano Observatory