The Climate & Geography Of The Aleutian Islands

An eruption of Cleveland Volcano in the Aleutians as seen from the International Space Station

The Aleutian Islands off Alaska’s southwest coast represent a true bridge over troubled water, albeit a broken one. Early North American inhabitants are thought to have crossed the land bridge over the Bering Sea from Europe thousands of years ago. Today, the land mass has been splintered into some 300 islands, spaced irregularly as if a careless giant had lifted and dropped it. The area attracts few tourists because of its geographic isolation and wild weather, but enthralls the initiated with its volcanoes, thick vegetation and vast and varied native wildlife.

A Broken Chain

The Aleutians are an archipelago of hundreds of volcanic islands thrusting some 1,300 miles into the Pacific Ocean and Bering Sea from Alaska’s southwest tip, a length almost equal to that of the West Coast of the United States. Most of the islands fall within the boundaries of the Alaska Maritime National Wildlife Refuge. Geologists view them as separated into island groups. The Fox island group contains the largest land masses: the islands of Attu, Unalaska, Umnak and Akun. The total area of the Aleutian Islands includes 6,821 square miles.


The Aleutian Islands were birthed in fire. Straddling the boundary between the Pacific and North American tectonic plates, the land was built by volcanic activity that continues to this day. Steep volcanoes rising to heights of over 6,000 feet crown the sedimentary islands, and volcanic cones abound in the northern islands. The archipelago curves southwest as it first leaves Alaska’s mainland, but curves back up at the tip as is typical of volcanic island chains. The Aleutian coastline is craggy and eroded; sea cliffs rise sharply into mountains. Landings can be perilous, the stuff of adventure novels.

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If you have never traveled Alaska’s expanse, it is difficult to fathom the enormity of the state; were it divided into two pieces, each would be larger than Texas. The state’s 586,000 square miles span several climate zones. Travelers to the Aleutians do not experience the intense cold known in central Alaska where temperatures regularly dip below minus 50 degrees Fahrenheit. The entire area is in the maritime climate zone, with about 2 feet of rain every year. Temperatures average 45 to 65 degrees Fahrenheit in summer, 10 to 35 degrees in winter. Wind and fog reign unfettered, however, especially in the regions that face the Bering Sea, where winter storms may rage to 100 mph.

Wildlife and Flora

Although the Aleutians landmass once was home to giant sequoias, that was 11 million to 25 million years ago. In modern times, wind and harsh conditions keep the tree population small and stunted. The only trees present on the islands are shrubby willows and a few dozen conifers that remain from the thousands planted on the island by Russians in the 1800s and later by the United States. The sole forest in the Aleutians, the Adak National Forest, consists of 33 trees, none over 17 feet tall. Instead, visitors find lush, herbaceous meadows and thick peat near the coast. The wildlife supported by the ecosystem is astonishing in range and diversity. The Aleutians are the nation’s premier seabird nesting refuge, with seabird colonies of global importance. Some 3 million seabirds breed in the islands, including the puffin. Mammals like sea otters, sea lions and harbor seals frequent the island waters that are also home to fish like salmon, halibut, cod, herring, perch, sand lance, sablefish, yellow fin sole and pollock.

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