Top 10 volcanoes in Alaska: America's largest volcanic frontier
Alaska sits along the longest stretch of the Pacific Ring of Fire under American jurisdiction. About 130 active or potentially active volcanoes line the arc that bends from the Aleutian Peninsula through Cook Inlet to Wrangell-St. Elias. Many of them are unreachable by road. Almost all are watched by the Alaska Volcano Observatory, partly because they sit beneath the major flight paths between North America and Asia. Here are ten of the most significant.
Mount Redoubt
A 3,100 m stratovolcano in the Aleutian Range that overlooks Cook Inlet, an hour by air from Anchorage. Redoubt erupted in 1989-90 and again in 2009; the 1989 event briefly stalled all four engines of a KLM 747 that flew through its ash plume. The plane recovered and landed at Anchorage, and the incident helped define modern aviation ash-protocols worldwide.
Mount Spurr
110 km west of Anchorage in the Chigmit Mountains. The 1992 eruption of the Crater Peak vent dropped centimetres of ash on Anchorage and grounded flights for days. Spurr is one of the volcanoes that the city's air-quality forecasters watch closely; on a clear day its snow-capped cone is visible from downtown.
Mount Augustine
A small island volcano in Cook Inlet that erupts every twenty to forty years and tends to be photogenic doing it. Augustine's 2006 eruption was extensively studied — accessible enough by helicopter to be instrumented, dangerous enough to matter. The whole island is essentially the cone, with a fishing-camp shoreline.
Novarupta
The volcano behind the largest eruption of the twentieth century, in 1912. Novarupta erupted in the Katmai region of the Alaska Peninsula, draining magma from beneath Mount Katmai 10 km away and creating the Valley of Ten Thousand Smokes. The eruption ejected about 30 km³ of magma — ten times the volume of Mount St Helens 1980.
Mount Katmai
The collapse caldera left behind when Novarupta drained its magma chamber. Katmai itself did not erupt explosively in 1912; instead its summit dropped 800 m as the underlying magma migrated to Novarupta. The crater lake that fills the caldera now is one of the more striking volcanic-collapse landscapes on Earth.
Mount Pavlof
A near-perfectly conical stratovolcano in the western Alaska Peninsula, one of the most consistently active in the United States. Pavlof erupts every few years — 1996, 2007, 2013, 2016, 2021 — usually with ash columns of 10 to 12 km that prompt aviation alerts but rarely affect ground populations.
Cleveland Volcano
A stratovolcano in the central Aleutians, frequently active, often shrouded in cloud. Cleveland's eruptions tend to be small but unpredictable; the volcano has no permanent instrumentation because of access difficulties and most monitoring is by satellite. For travellers between Anchorage and Asia, Cleveland's ash plumes are a frequent flight-routing concern.
Mount Wrangell
A massive shield volcano in eastern Alaska, 4,317 m high, last known to erupt in 1900. Wrangell sits in Wrangell-St. Elias National Park, the largest national park in the United States. Steam plumes from the summit are visible from the McCarthy road in winter when the air is dry enough to carry them.
Mount Iliamna
A snow-and-glacier-clad stratovolcano on the western side of Cook Inlet, paired visually with Redoubt across the water from Anchorage. Iliamna has not erupted in historical times but fumaroles near the summit are continuously active. The Glacier that drapes its eastern flank is one of the more striking ice-on-volcano landscapes in North America.
Bogoslof
A small island volcano in the eastern Aleutians that intermittently rebuilds itself above sea level and is intermittently destroyed by its own eruptions. The 2016-17 eruption added about 1 km of new shoreline. Bogoslof is a constant reminder that volcanoes in the Aleutians do not need to be on a recognised island to matter.
See them on the map
Open the map and trace the Aleutian arc from the Alaska Peninsula westward. The pattern is one of the cleanest examples on Earth of a subduction-zone volcanic arc — Pacific Plate diving beneath the North American Plate, magma rising through the overlying crust, producing the chain of cones you see.