Alert level raised following Semisopochnoi explosion

August 22, 2022

The Alaska Volcano Observatory reported that a short-lived explosion of the Semisophochnoi Volcano occurred Sunday afternoon at 1:47 p.m. Webcam images near the volcano show the plume of ash ejecting high into the sky, although satellite imagery showed no visible ash plume. As a result, the ash stayed below 20,000 feet above sea level.

By Aaron Morrison with KTUU

Semisopochnoi has been fairly active over the last year, although the has been fairly quiet since June 12. Due to the recent eruption, the Aviation Color Code and Volcano Alert Level are being raised to Orange/Watch.

It’s important to remember that small eruptions can occur again with little to no warning. When this happens, minor ash deposits can be expected within the vicinity of the active north crater of Mount Cerberus and ash clouds are usually under 10,000 feet.

Semisopochnoi is an island in the western Aleutian Islands, which contains a group of cones within a caldera complex. It is the largest young volcanic island in the western Aleutians and is made of a variety of volcanic landforms.

A historic eruption of Semisopochnoi was reported in 1873, with at least four others which may have occurred in the previous hundred years.

Return to list.