Mount Cleveland, located on the remote Chuginadak Island about 45 miles from the Aleutian community of Nikolski, is among Alaska's most active volcanos. It has erupted at least 24 times since 1828. In 1944, Cleveland became responsible for the only human fatality directly related to volcanic activity in Alaska, when a sergeant in the 11th Air Force, stationed on the island in World War II, was likely killed by a mudslide during an eruption.

The 5,676-foot peak has experienced 11 eruptive events since 2000 alone, and its regular activity has led to several more raised alerts in the last two years.

In 2011, the alert level at Cleveland was raised to "orange" -- indicating heightened activity with the potential for eruption, including the growth of a lava dome -- three times, in August, September and December. That last alert came in the wake of Cleveland blasting out a cloud of ash to 15,000 feet on Dec. 29, observed by satellite imagery -- the primary method of observing Cleveland, since there is no real-time monitoring equipment based on the island. An eruption in 2001 launched an ash cloud 39,000 feet into the air.

That December eruption cleared away much of a lava dome that had been steadily building throughout the year, but in Jan. 2012, the activity level was raised again when a new lava dome about 130 feet in diameter was observed building inside the volcano's crater. After other raised alert levels, Cleveland erupted again, launching ash 35,000 feet into the air on June 19, 2012.

For the most recent updates on Mount Cleveland and for aviation alerts, check the Alaska Volcano Observatory page.