Alaska Volcano Observatory raises Aviation Color Code to Orange, Alert Level to Watch for Mount Cleveland

The Alaska Volcano Observatory has raised Cleveland Volcano's Aviation Color Code to Orange and the Alert Level to Watch following observations that the small lava dome in its summit crater has resumed growth and now fills the floor of the crater.

Alaska's Cleveland Volcano | Courtesy of the Alaska Volcano Observatory

Observers from the Alaska Volcano Observatory added that there is a persistent thermal anomaly that has been observed since September 3, probably marking the timing of resumed lava dome growth.

As of August 30, the size of the dome when it appeared to have stopped growing was approximately 80 meters (262 feet)in diameter. On September 6, the dome measured approximately 120 meters (394 feet) in diameter.

Scientists from the Alaska Volcano Observatory said that if dome growth continues, lava flows onto the flanks of the volcano may develop but would not be hazardous to aviation. They explained that the presence of the lava dome increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. Short-lived explosions could produce an ash cloud that exceeds 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours, the scientists added.

Cleveland Volcano, a 1,730 m (5,676 ft) high land mass situated in the Aleutian Islands of Alaska, is one of the most active of the 75 or more volcanoes in the larger Aleutian Arc. It has reportedly erupted at least 21 times in the last 230 years. Its most recent eruption was in July 2011.