The USGS has raised the current volcano alert level to WARNING and the current aviation code to RED at the Shishaldin Volcano in Alaska, where trans-Pacific flights could be at risk from hazards of dangerous volcanic ash.
According to the Alaska Volcano Observatory (AVO) with USGS, an ash cloud from Shishaldin Volcano reaching 25,000′ above sea level and rising was reported by a pilot at at 8:42 am AKDT. Satellite data suggests that the cloud may be as high as 30,000 ft above sea level. The cloud is visible in satellite data moving towards the southeast and lightning associated with the ash cloud has been detected.
“Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano,” the AVO warns.
Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.
Volcanic ash can be very hazardous to aviation interests! https://t.co/3RLPr8fnld
— the Weatherboy (@theWeatherboy) September 5, 2023
Volcanic ash can create problems on the ground and in the sky. Volcanic ash can create significant harm to jet engines that fly through them or boat and automobile engines that ingest air-filled air. Volcanic ash is hard and abrasive, and can quickly cause significant wear to various airplane parts such as propellers, turbo-compressor blades, and even cockpit windows. Because volcanic ash particles have a low melting point, it can melt in the combustion chamber of a jet engine, creating a ceramic or glass-like glaze that then sticks to turbine blades, fuel nozzles, and combustors. A jet engine that ingests just a small amount of ash could suffer from total engine failure. Overheating and engine failure is also possible in cars and trucks since volcanic ash can infiltrate nearly every opening in a vehicle. Ash is also very abrasive; ash caught between windshields and wiper blades will scratch and permanently mark the windshield glass, and windows are susceptible to scratching each time they are raised, lowered, and cleaned.
In the U.S., the USGS and volcano observatory units are responsible for issuing Aviation Codes and Volcanic Activity Alert Levels. Aviation Codes are green, yellow, orange, or red. When ground-based instrumentation is insufficient to establish that a volcano is at a typical background level of activity, it is simply “unassigned.” While green means typical activity associated with a non-eruptive state, yellow means a volcano is exhibiting signs of elevated unrest above known background levels. When a volcano exhibits heightened or escalating unrest with the increased potential of eruption, it jumps to orange. Finally, when an eruption is imminent with significant emission of volcanic ash expected in the atmosphere or an eruption is underway with significant emission of volcanic ash into the atmosphere, the code becomes red. Volcanic Activity Alert levels are normal, advisory, watch, or warning. As with aviation codes, if data is insufficient, it is simply labeled as “unassigned.” When the volcano is at typical background activity in a non-eruptive state, it is considered normal. If the volcano exhibits signs of elevated unrest above background level, an advisory is issued. If a volcano exhibits heightened or escalating unrest, a watch is issued while a warning is issued when a hazardous eruption is imminent.
Within the United States, the USGS tracks 169 potentially active volcanoes, most of which are in Alaska. Alaska is home to many volcanoes, though; there are more than 130 volcanoes and volcanic fields which have been active within the geologically young last 2 million years. 50 have been active since the mid 1700s and AVO studies those too. Another place famous for its volcanoes is Hawaii; on the Big Island of Hawaii, Kilauea, Mauna Loa, and Hualalai are considered active and potential threats. Volcanoes in Hawaii are monitored by the Hawaii Volcano Observatory (HVO). The U.S. is only home to a fraction of the world’s volcanoes: according to USGS, there are normally around 2 dozen erupting volcanoes around the world at any given time. The USGS says there are about 1,500 potentially active volcanoes worldwide, with about 500 of the 1,500 erupting in modern historical times.
