Mountains of Ice

Mountains of Ice

Credit: Courtesy Ted Scambos and Rob Bauer, NSIDC

Although they've been on the retreat since Earth's last ice age, glaciers still have the power to amaze. These frozen masses of ice cover 10 percent of Earth's land area, appearing on every continent, even Africa, according to the National Snow and Ice Data Center (NSIDC). Here are a few notables. (Above, glacial ice at Parque Nacional los Glaciares in Argentina.)

Aletsch Glacier, Switzerland

Aletsch Glacier, Switzerland

Credit: Stephanie Pappas

The largest and longest glacier in Europe snakes among mountain peaks like a river frozen in time. Glaciers form when layers of snow build upon one another year after year. Eventually, the lower layers re-crystallize into ice. Tiny air bubbles in the ice preserve bits of ancient atmosphere, making glaciers an important research tool for scientists looking to understand the climate of thousands of years ago.

Ice Fields of Kilimanjaro

Ice Fields of Kilimanjaro

Credit: Dalia Kirschbaum, NASA Goddard Space Flight Center via Imaggeo

Snow-covered glaciers on the summit of Mount Kilimanjaro in Tanzania. Unfortunately, Kilimanjaro glaciers are retreating rapidly in recent years, according to research published in November 2009 in the journal Proceedings of the National Academy of Sciences. Between 1912 and 1953, the mountain's ice cover shrank by about 1 percent each year. Between 1989 and 2007, that rate increased to 2.5 percent per year.

Briksdal Glacier

Briksdal Glacier

Credit: Jorge Mataix-Solera, Universidad Miguel Hernandez, Elche - Alicante - Spain, via Imaggeo

The Briksdal Glacier in Norway. According to NSIDC, glacial ice gets its blue color when it becomes very dense. White-colored glacial ice has many tiny air bubbles embedded amidst its ice crystals. As the ice becomes dense, those air bubbles get forced out. The ice that is left behind absorbs all colors in the ice spectrum except blue.

Glacial Tunnel

Glacial Tunnel

Credit: Alex Gardner

An ice cave or englacial melt channel. This ice cave was formed by meltwater flowing within the glacier ice. Belcher Glacier, Devon Island, Nunavut, Canada.

Cold Camp

Cold Camp

Credit: Zervas Efthimios, Democritus University of Thrace, Xanthi, Greece, via Imaggeo

A mountain-climbing expedition makes camp on a glacier on the slopes of Mount Elbrus, an inactive volcano in the Caucasus mountains of Russia.

Breiðamerkurjökull

Breiðamerkurjökull

Credit: Andreas Tille, Wikimedia Commons

Iceland is known for its glaciers with tongue-twisting names. Breiðamerkurjökull is in the southeastern part of the country.

Blue Lagoon

Blue Lagoon

Credit: Stefan Wirtz, Trier University, Germany via Imaggeo

Breiðamerkurjökull terminates at Jökulsárlón, the largest glacial lagoon in Iceland. The glacier expanded between the 1600s and the 1900s, during a cold period known as "The Little Ice Age." Warming temperatures since sent the glacier into retreat. Starting in about 1935, Jökulsárlón began to form in its wake. The glacial lagoon is now about 650 feet (200 meters) deep where the glacier's nose once was.

Fog & Ice

Fog & Ice

Credit: Qiao Liu, Institute of Mountain Hazards and Environment (IMHE), Chinese Academy of Sciences, China

Fog crosses Hailuoguo glacier on Mount Gongga in the Sichuan province of China.

Alaskan Ice

Alaskan Ice

Credit: Katrin Bentel, Norwegian University of Life Sciences, via Imaggeo

An aerial view of the Kennicott and Rott glaciers in the Wrangell Mountains of Alaska. Most of the United States' glaciers are located in Alaska.

Bering Up

Bering Up

Credit: NASA Image by Robert Simmon, based on data provided by the Landsat 7 Science Team

The largest glacier in North America is Alaska's Bering Glacier, which currently terminates in the Vitus Lake about 6 miles (10 km) from the Gulf of Alaska.

The retreat of the Bering glacier, which has been ongoing since 1900, has the side effect of increasing the number of earthquakes in the area. The weight of the glacier once stabilized the boundary between the Pacific and North American tectonic plates, which meet along the Alaska coast. As the ice retreated, that compression disappeared, enabling the two plates to move against one another more freely.

Blue Melt

Blue Melt

Credit: Romain Schläppy, Paris, France, via Imaggeo

Meltwaters flow from the Trift glacier in the Swiss alps.

Glacier Sunrise

Glacier Sunrise

Credit: R. Dwi Susanto, Lamont Doherty Earth Observatory of Columbia University, via Imaggeo

Even Indonesia has glaciers — for now, at least. The ice fields of Puncak Jaya in Papua, Indonesia are, like other glaciers worldwide, shrinking

Argentine Ice

Argentine Ice

Credit: International Space Station. 2003 Upsala Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data

The Viedma, Agassiz, and Onelli glaciers are visible on this International Space Station photograph of Argentine Patagonia.

Ghosts in a Glacier

Ghosts in a Glacier

Credit: John Goodge

A web of cracks in meltwater ice found along the edge of Byrd Glacier in Antarctica. The 85 mile ( 137 kilometers) long glacier flows into the Ross Ice Shelf. About the size of France, the Ross Ice Shelf is the largest ice field in Antartica.

Iceberg Grotto

Iceberg Grotto

Credit: Photographic Archive, Alexander Turnbull Library

A grotto in an iceberg, photographed during the British Antarctic Expedition of 1911-1913. Photographer Herbert Ponting snapped this photograph in January 1911.

Giant Glacier

Giant Glacier

Credit: Mr. Fred Walton, NOAA

NOAA researchers took this picture of an enormous glacier while flying over the Antarctic landscape to McMurdo Station.

Ice Arch

Ice Arch

Credit: Glenn Grant, National Science Foundation

A natural glacial arch at Norsel Point on Anvers Island, Antarctica.

Centuries of Ice

Centuries of Ice

Credit: State Library of New South Wales

Almost a century ago, Antarctic explorers were awed by the natural ice sculptures they found on the continent. Frank Hurley took this photograph during Ernest Shackleton's "Endurance" Expedition in 1915. The expedition ship became trapped in sea ice during the voyage, forcing the crew to camp on ice for five months. Shackleton and a few crew members eventually took a lifeboat to South Georgia Island for help, a treacherous open-ocean journey that paid off when he was able to rescue all of his men.

Cracked

Cracked

Credit: Shad O’Neel, USGS

Crevasses in the Guyot glacier near Ice Bay, Alaska.

Aletsch Glacier

Aletsch Glacier

Credit: Frank Paul

The Aletsch Glacier of Switzerland is the largest in the Alps, but scour marks on the valley reveal that the ice used to extend much higher.

Upsala Glacier

Upsala Glacier

Credit: Etienne Berthier

The ice of Argentina's Upsala Glacier appears almost neon blue.

Canadian Glacier

Canadian Glacier

Credit: Alex Gardner

A small valley glacier exiting the Devon Island Ice Cap in Nunavut, Canada.

Upsala Glacier

Upsala Glacier

Credit: Etienne Berthier

Argentina's Upsala Glacier in Los Glaciares National Park has experienced rapid retreat.

Perito Moreno Glacier

Perito Moreno Glacier

Credit: Etienne Berthier

Argentina's Perito Moreno Glacier is the third-largest reservoir of freshwater in the world.

Perito Moreno Elevation

Perito Moreno Elevation

Credit: Etienne Berthier

The cracks and crevices of Argentina's Perito Moreno Glacier illustrate the slow movement of the ice.

Digging Into a Glacier

Digging Into a Glacier

Credit: Alex Gardner

Researchers dig a 13-foot (4 meter) pit into the snow of the Devon Island Ice Cap in Nunavut, Canada to examine annual snow layers.

Watching a Glacier

Watching a Glacier

Credit: Alex Gardner

A time-lapse camera keeps an eye on Nunavut, Canada's Belcher Glacier. Ground observations help researchers understand how much ice is calving into the ocean.

Sverdrup Glacier

Sverdrup Glacier

Credit: Alex Gardner

An aerial view of Nunavut, Canada's Sverdrup Glacier, which flows from the Devon Island Ice Cap to the ocean.

Alaska Meltwater

Alaska Meltwater

Credit: W. Tad Pfeffer

Meltwater ponded at the Columbia Glacier in Alaska, as seen in July 2008.

Columbia Glacier

Columbia Glacier

Credit: W. Tad Pfeffer

Crevasses in the accumulation zone of the Columbia Glacier in Alaska. The accumulation zone is the area of the glacier where snow accumulates and packs into ice.

Greenland's Glaciers

Greenland's Glaciers

Credit: Frank Paul

Peripheral glaciers and ice caps in eastern Greenland. In the background, the ice sheet is visible, with glacier fingers protruding.

Columbia Glacier Terminus

Columbia Glacier Terminus

Credit: W. Tad Pfeffer

The terminus of Alaska's Columbia Glacier. The glacier retreated 8.7 miles (14 km) between 1984 and 2004.

Glacier Iceberg

Glacier Iceberg

Credit: W. Tad Pfeffer

A stranded iceberg from the Columbia Glacier in Prince William Sound, Alaska.