Pool on the Root Glacier
Pool on the Root Glacier


When describing glaciers in Wrangell St. Elias National Park and Preserve, superlatives are evident. Within park boundaries exists the nation's largest glacial system, with glaciers covering 35 percent of the parklands. In summer, these glaciers contribute a significant portion of the rivers' high runoff and heavy sediment load. During the winter, glacial melt reduces and many rivers run with clear water.

Glaciers are the headwaters for many of the river systems that flow like arteries through the park. They are heavy with glacier silt and sediment, causing them to braid as one channel begins to fill with sediment forcing the water to switch to a new channel. Glaciers themselves are often referred to as rivers of ice. They flow down mountain valleys and, in the case of tidewater glaciers, into the sea.

Notable Glaciers in Wrangell-St. Elias:

BAGLEY ICEFIELD: This massive icefield encompasses multiple glaciers and is 127 miles long, 6 miles wide, and up to 3,000 feet thick!
NABESNA GLACIER: This is the world's longest interior valley glacier, stretching over 53 miles long.
MALASPINA GLACIER: North America's largest piedmont glacier (formed at the base of a mountain rather than enclosed by a valley). It covers an area larger than Rhode Island!
HUBBARD GLACIER: Flowing over 75 miles and calving into the sea with a face 6 miles wide, this glacier near Yakutat is the longest tidewater glacier in North America.

Hubbard Glacier

The Hubbard Glacier is North America's largest tidewater glacier.

  • It is 76 miles long, 7 miles wide and 600 feet tall at its terminal face (350 feet exposed above the waterline and 250 feet below the waterline).
  • The Hubbard Glacier starts at Mt. Logan (19,850 ft) in the Yukon Territory of Canada and ends within Wrangell-St. Elias National Park & Preserve. Mt. Logan is the 2nd tallest mountain on the North American continent.
  • The glacier was named in 1890 for Gardiner Hubbard, the first president of the National Geographic Society.
  • The Hubbard Glacier’s terminus is currently in a stable position after advancing over the last 100 years, and the glacier continues to thicken.
  • The ice you see at the terminal face originally fell as snow, as much as 500 years ago, and the glacier is over 2,000 feet thick at some locations.
  • Glacier positions:

2002 and 1986 - Gilbert Point
100 years ago - 2 miles east of Osier Island
200 years ago - retreated past Haenke Island
300 years ago - retreated to Pt. Blizhni
700 years ago - advanced to fill the entire Yakutat Bay

Why Does the Hubbard Glacier Advance and Retreat?

During the summer of 2002 the Hubbard Glacier near Yakutat pulsed forward, closing Russell Fiord from the sea. The massive ice dam that formed was later breached and washed out by water retained behind it, reconnecting the fiord to the ocean. Rather than being an event that took hundreds of years, this drama played out in the course of a couple of months. This short-term fluctuation was small, however, compared with the overall terminus advance that occurred over the last 100 years. This recent advance is in contrast with the behavior of most glaciers in Alaska and worldwide, which are retreating. Why?
All glaciers adjust their overall size to reach a balance between the amount of ice they gain (as snowfall) and the amount of ice they lose. Simply, when the glacier gains more ice than it loses, it will advance. Conversely, when a glacier loses more ice than it gains, it retreats. Most glaciers in Alaska lose mass primarily by melt, and are retreating because melt rates have increased as the climate has warmed. But tidewater glaciers like Hubbard Glacier also lose mass by another mechanism—calving of icebergs into the sea. This interaction with the ocean is complicated and only partly driven by climate. Tidewater glaciers therefore grow and shrink in response not only to climate, but also in response to the particular geometry of their tidewater glacier terminus.

Medial moraines on the Kennicott Glacier
Medial moraines on the Kennicott Glacier

NPS / Neal Herbert

Why does the Kennicott Glacier look so dirty?

Many people are surprised by their first glimpse of the Kennicott Glacier. Instead of the clean white and blue ice they envisioned, they are confronted with a rough, rocky, brown moonscape. Is that really a glacier out there? It is indeed; the surface moraine of dirt and rocks is only a few inches to a few feet deep, while the ice underneath is still hundreds of feet thick. How did the glacier get so dirty? Although landslides and avalanches contribute, it all comes down to movement, melting and medial moraines. The Kennicott Glacier moves 26 miles from the high peaks of the Wrangells to the valley floor. Many glacial tributaries feed into this river of ice, each carrying its own load of debris as it carves its way downwards. These tributary debris loads form the medial moraines of the Kennicott Glacier. The rocks and dirt on these medial moraines affect the melting of the ice underneath. If less than 6 inches of debris cover the ice, the dark layer will transfer heat and accelerate melting. If the debris is more than 6 inches thick, it will instead insulate and protect the ice. As the glacier moves, the debris cover also moves, eventually spreading over the ice. The moraines merge just north of Kennecott, forming the surface moraine you see now. Even with its protective surface moraine, the Kennicott Glacier is melting fast. When the Kennecott Mines were at their peak in the early 1900's, the glacier towered over the mining camp, in some places even taller than the mill building. But it is deflating quickly and now we look down on the glacier, even at street level. One study showed that the Kennicott Glacier lost 115 to 330 feet (35 - 100 meters) in just 50 years, from 1957 to 2007. Depending on location, the Kennicott Glacier is currently losing 6 to 23 feet (2 - 7 meters) of ice a year, a dramatic example of a changing climate.


Malaspina Glacier National Natural Landscape

Tlingit: Sít' Tlein, meaning 'big glacier'

Wrangell - St Elias National Park & Preserve

Malaspina Glacier
Malaspina Glacier


Malaspina Glacier, located within Wrangell-St. Elias National Park on the coast near Icy Bay and Yakutat Bay, is the largest piedmont glacier in North America. As one of the largest glaciers outside the ice cap regions of the world, it is 1,075,409 acres in size, larger than the state of Rhode Island. It provides classic examples of glacial mechanisms and fluctuations. This large body of ice has been noted by explorers concerned with navigation of the western coast of North America for more than two centuries. It was designated as a National Natural Landscape in 1968.

Malaspina is the colonial name for the glacier, in honor of Alessandro Malaspina, a Tuscan explorer in the service of the Spanish Navy, who visited the area in 1791. In 1874, W.H. Dall, of the U.S. National Geodetic Survey, bestowed the name "Malaspina Plateau". Originally, its indigenous name in Tlingit is Sít' Tlein, meaning 'big glacier'.

Latitude: 59.971466064453125 Longitude: -140.52377319335938

Ongoing research (article series, nps website)


Seeing & Exploring Glaciers

Hikers should not attempt to cross glaciers without training and proper equipment, including crampons, ropes, and ice axes. Clean ice and even debris-covered moraines will turn slick and dangerous during or after a rain.

Please discuss your plans with a park ranger before undertaking glacial travel or mountain peak ascents. Guides are available for these activities and can be used to gain experience.

A great way to see the park's glaciers and icefields is from the air. There are a number of flightseeing operators that offer a variety of spectacular tours.

The only way to see the Hubbard Glacier is to visit Yakutat, Alaska. You can see it by boat or by air. Several cruise ship companies include the Hubbard Glacier on their Alaska cruise itineraries.

Glacier Ice Features

Glacier Ice Caves
Glacier Ice Caves

Melting at the margin of a glacier may cause small caves to form, creating a tunnel between the ice and bedrock or sediment.

Ice Falls
Ice Falls

Ice falls in a glacier are like water falls in a river and they form in steep sections of the glacier.


Jökulhlaups (an Icelandic word pronounced yo-KOOL-lahp) are glacial outburst floods that occur when a glacial meltwater lake breaches.


Additional Information...

NPS Subjects: Investigate Glaciers - Explore glaciers through images, panoramas, video, sounds, and text.

The Life of a Glacier by the National Snow and Ice Data Center.

Glaciers in Alaska's National Parks by the National Park Service Alaska Regional Office.

Glacial Dynamics by the Southeast Alaska Inventory & Monitoring Network.

NPS Articles: Status and Trends of Alaska National Park Glaciers by Michael G. Loso, Anthony Arendt, Chris Larsen, Nate Murphy, and Justin Rich.

Glaciers: Why Should We Care? YouTube video with Michael Loso, NPS Physical Scientist


Additional Resources

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    Last updated: January 29, 2024

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    Wrangell-St. Elias National Park & Preserve
    PO Box 439
    Mile 106.8 Richardson Highway

    Copper Center, AK 99573


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