Scientists have raised an aviation alert level around a remote Alaskan volcano after a small eruption produced an ash cloud several miles high.

Cleveland Volcano, on the Aleutian Islands southwest of mainland Alaska, erupted briefly Tuesday afternoon, creating an ash cloud at an estimated height of 23,000 feet above sea level, said Steve McNutt, a volcano seismologist at the Alaska Volcano Observatory and the University of Alaska Fairbanks.

The observatory on Tuesday raised its color-coded alert for aviators to orange, the third most serious of four levels, and warned on its website that “additional sudden explosions of blocks and ash are possible with little or no warning,” CNN reported.

A more serious eruption, especially one that spews ash above 30,000 feet, could affect air travel.

McNutt said the vast majority of air freight between Asia and North America and between Asia and Europe flies over Alaskan airspace. Also, passenger flights take about 20,000 passengers over Alaskan airspace daily, he said.

The volcano makes up the western half of uninhabited Chuginadak Island, part of the Aleutian Island chain in the Bering Sea. It is about 45 miles west of Nikolski and 940 miles southwest of Anchorage.

The alert level has bounced between orange and the lower step, yellow, several times in the past year. The volcano’s most recent significant eruption happened in February 2001, with three explosions that led to ash clouds as high as 7.5 miles above sea level

Ref.110.110.110.1260