Malaspina Glacier Deep Dive
The Malaspina, on the Alaska–Yukon coast, is the largest piedmont glacier in the world. A piedmont glacier is one that has flowed out of a confined mountain valley onto a flat plain and spread into a wide lobe. The Malaspina's lobe is about 65 km across and 45 km from the foot of the St. Elias mountains to the Gulf of Alaska — roughly the area of the U.S. state of Rhode Island.
Geography
The Malaspina is fed primarily by the Seward Glacier from Mount St. Elias and Mount Logan. Once the ice spills out onto the coastal plain, it ceases to be a true valley glacier and becomes a broad, low-gradient sheet. The southern margin nearly reaches the Pacific, separated from open water only by a thin coastal strip.
Forest on the ice
Parts of the Malaspina's stagnant margin are buried under debris deep enough to support a forest. Spruce trees several decades old grow on top of ice many tens of metres thick. The trees lean and fall as the surface beneath them subsides — a slow, ongoing disturbance pattern unique to debris-covered piedmont ice.
History
Russian Captain Alessandro Malaspina sighted and named the coastline in 1791. The glacier was first crossed by an American expedition in 1897 attempting Mount St. Elias. By the time of the 1958 Cordillera Huayhuash and other Alaskan-style maps, the Malaspina was a textbook example of a piedmont glacier.
Mass balance and change
The Malaspina is thinning. Mid-tongue surface elevation has dropped tens of metres in recent decades, and the seaward margin is partially detached from the ice mass behind. Some scientists have warned that catastrophic retreat could expose new tidewater to ocean processes if a marine connection opens.
Visiting
Most visitors see the Malaspina from the air. Flightseeing operators from Yakutat fly over the entire piedmont, the Seward feeder and the St. Elias range. Hikers can reach the southern margin from the Yakutat road system, but the ice itself is best appreciated from above.
Wrangell-St. Elias National Park
Most of the Malaspina lies in Wrangell-St. Elias, the largest national park in the United States. The park does not have extensive infrastructure; planning involves bush planes, marine charters and self-sufficient itineraries.
Why it matters
The Malaspina represents what happens when a major mountain glacier escapes its valley. As a global archetype, it features in every textbook on glacier morphology. As a real-world climate indicator, it is one of the most-watched bodies of ice on the Pacific coast.
Plan your next trip
The interactive map shows the Seward feeder, the piedmont lobe outline, flightseeing operator hubs in Yakutat and the section of coastline where the southern margin is most visible from the road.