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A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity. Typically, glaciers exist and may even form in areas where:
Over multiple decades this continuing accumulation of snow results in the presence of a large enough mass of snow for the metamorphism from snow to glacier ice process to begin. Glaciers are classified by their size (i.e. ice sheet, ice cap, valley glacier, cirque glacier), location, and thermal regime (i.e., polar vs. temperate). Glaciers are sensitive indicators of changing climate.
Learn more: USGS Water Science School: Glaciers and Icecaps
Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years. Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and related data suggest that all of southern Greenland and...
Based on the most recent comprehensive survey in 2011, there were about 27,000 glaciers in Alaska. However, the number of glaciers is a misleading statistic. Scientists are more interested in total glacial land coverage as a measure. The number of glaciers is less important since large ones can split up into several as they retreat. The amount of area glaciers occupy in Alaska is trending downward...
Mount Rainier, Washington, at 14,410 feet (4,393 meters), the highest peak in the Cascade Range, is a dormant volcano whose glacier ice cover exceeds that of any other mountain in the conterminous United States. Mount Rainier has approximately 26 glaciers. It contains more than five times the glacier area of all the other Cascade volcanoes combined. Mount Baker (Washington) at 10,778 feet (3,285...
No one knows for sure. In the Devils Hole, Nevada paleoclimate record, the last four interglacials lasted over ~20,000 years with the warmest portion being a relatively stable period of 10,000 to 15,000 years duration. This is consistent with what is seen in the Vostok ice core from Antarctica and several records of sea level high stands. These data suggest that an equally long duration should be...
The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old The age of the oldest glacier ice in Greenland is more than 100,000 years old The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old. Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100...
No--most of interior Alaska, south of the Brooks Range and north of the Alaska Range, was a non-glaciated grassland refuge habitat for a number of plant and animal species during the maximum Pleistocene glaciation. This ice-free corridor also provided one route for humans to move into North America. Learn more: USGS Water Science School - Glaciers: Things to Know
Yes, ice worms do, in fact, exist! They are small worms that live in glacial ice in Alaska, Washington, Oregon, and British Columbia; they have not been found in glaciers elsewhere. Contrary to stories and songs, they do not give glacier ice its blue color and they don't grow to lengths of 50 feet. These myths were made popular by poet Robert Service and the annual Cordova Iceworm Festival in...
Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snowflake is a...
Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears. Learn more: USGS Water Science School - Glaciers: Things to Know
About 2.1% of all of Earth's water is frozen in glaciers. 97.2% is in the oceans and inland seas 2.1% is in glaciers 0.6% is in groundwater and soil moisture less than 1% is in the atmosphere less than 1% is in lakes and rivers less than 1% is in all living plants and animals. About three-quarters of Earth's freshwater is stored in glaciers. Therefore, glacier ice is the second largest reservoir...
Glaciers exist on every continent except Australia. Approximate distribution is: 91% in Antarctica 8% in Greenland Less than 0.5% in North America (about 0.1% in Alaska) 0.2% in Asia Less than 0.1% are in South America, Europe, Africa, New Zealand, and Indonesia.
Glaciers act as reservoirs of water that persist through summer. Continual melt from glaciers contributes water to the ecosystem throughout dry months, creating perennial stream habitat and a water source for plants and animals. The cold runoff from glaciers also affects downstream water temperatures. Many aquatic species in mountainous environments require cold water temperatures to survive. Some...
A path near the Mendenhall Glacier Visitor Center in Juneau, Alaska is completely submerged by floodwaters from a glacial lake outburst flood.
A path near the Mendenhall Glacier Visitor Center in Juneau, Alaska is completely submerged by floodwaters from a glacial lake outburst flood.
A new rift is forming across the Petermann Glacier. If this rift connects to existing rifts, it could result in another large iceberg breaking free.
At the USGS EROS Center, we study land change, operate the Landsat satellites, and maintain the longest, continuously acquired collection of images of the Earth's land surface.
A new rift is forming across the Petermann Glacier. If this rift connects to existing rifts, it could result in another large iceberg breaking free.
At the USGS EROS Center, we study land change, operate the Landsat satellites, and maintain the longest, continuously acquired collection of images of the Earth's land surface.
These Landsat 8 images show the latest iceberg to break free in Antarctica's Pine Island. Warmer ocean waters are melting the ice from beneath, causing increasing instability.
These Landsat 8 images show the latest iceberg to break free in Antarctica's Pine Island. Warmer ocean waters are melting the ice from beneath, causing increasing instability.
Grinnell Glacier Mather Overlook 2008 in color.
Grinnell Glacier Mather Overlook 2008 in color.
Monitoring glaciers in Glacier National Park.
Monitoring glaciers in Glacier National Park.
Located on the northwestern coast of Greenland, Petermann Glacier covers 1,295 square kilometers (500 square miles). The glacier's floating tongue of ice extends from the lower right corner of the image toward the top center. At 15–20 kilometers (9–12 miles) wide and 70 kilometers (43 miles) long, it is the longest floating glacier in the Northern Hemisphere.
Located on the northwestern coast of Greenland, Petermann Glacier covers 1,295 square kilometers (500 square miles). The glacier's floating tongue of ice extends from the lower right corner of the image toward the top center. At 15–20 kilometers (9–12 miles) wide and 70 kilometers (43 miles) long, it is the longest floating glacier in the Northern Hemisphere.
USGS scientist shoots a repeat photograph of Grinnell Glacier in Glacier National Park to illustrate glacial recession due to impacts of climate change.
*note – logo on scientists hat is logo from USGS Northern Rocky Mountain Science Center, not private.
USGS scientist shoots a repeat photograph of Grinnell Glacier in Glacier National Park to illustrate glacial recession due to impacts of climate change.
*note – logo on scientists hat is logo from USGS Northern Rocky Mountain Science Center, not private.
Glaciers are Earth's largest reservoir of freshwater. As they change, so does global sea level. Alaska has one of the largest accumulations of glaciers anywhere on Earth outside of the Polar regions. For most of the past half century, Alaska has experienced a significant increase in temperature that has profoundly impacted its glaciers. Join USGS scientist Dr.
Glaciers are Earth's largest reservoir of freshwater. As they change, so does global sea level. Alaska has one of the largest accumulations of glaciers anywhere on Earth outside of the Polar regions. For most of the past half century, Alaska has experienced a significant increase in temperature that has profoundly impacted its glaciers. Join USGS scientist Dr.
Surprise Glacier (in background), Harriman Fiord, western Prince William Sound.
Surprise Glacier (in background), Harriman Fiord, western Prince William Sound.
Barry Glacier, Barry Arm, western Prince William Sound.
Barry Glacier, Barry Arm, western Prince William Sound.
Photographer Tad Pfeffer capturing images of Columbia Glacier in Prince William Sound, Alaska. He is looking down-glacier towards the ice front, which faces open water in the fjord. This open water is extremely rare, and has not happened again since 2005. The fjord is typically covered with iceberg debris, called mélange.
Photographer Tad Pfeffer capturing images of Columbia Glacier in Prince William Sound, Alaska. He is looking down-glacier towards the ice front, which faces open water in the fjord. This open water is extremely rare, and has not happened again since 2005. The fjord is typically covered with iceberg debris, called mélange.
Peter Haeussler prepares to measure the offset of a crevasse on the Canwell Glacier.
Peter Haeussler prepares to measure the offset of a crevasse on the Canwell Glacier.
Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years. Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and related data suggest that all of southern Greenland and...
Based on the most recent comprehensive survey in 2011, there were about 27,000 glaciers in Alaska. However, the number of glaciers is a misleading statistic. Scientists are more interested in total glacial land coverage as a measure. The number of glaciers is less important since large ones can split up into several as they retreat. The amount of area glaciers occupy in Alaska is trending downward...
Mount Rainier, Washington, at 14,410 feet (4,393 meters), the highest peak in the Cascade Range, is a dormant volcano whose glacier ice cover exceeds that of any other mountain in the conterminous United States. Mount Rainier has approximately 26 glaciers. It contains more than five times the glacier area of all the other Cascade volcanoes combined. Mount Baker (Washington) at 10,778 feet (3,285...
No one knows for sure. In the Devils Hole, Nevada paleoclimate record, the last four interglacials lasted over ~20,000 years with the warmest portion being a relatively stable period of 10,000 to 15,000 years duration. This is consistent with what is seen in the Vostok ice core from Antarctica and several records of sea level high stands. These data suggest that an equally long duration should be...
The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old The age of the oldest glacier ice in Greenland is more than 100,000 years old The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old. Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100...
No--most of interior Alaska, south of the Brooks Range and north of the Alaska Range, was a non-glaciated grassland refuge habitat for a number of plant and animal species during the maximum Pleistocene glaciation. This ice-free corridor also provided one route for humans to move into North America. Learn more: USGS Water Science School - Glaciers: Things to Know
Yes, ice worms do, in fact, exist! They are small worms that live in glacial ice in Alaska, Washington, Oregon, and British Columbia; they have not been found in glaciers elsewhere. Contrary to stories and songs, they do not give glacier ice its blue color and they don't grow to lengths of 50 feet. These myths were made popular by poet Robert Service and the annual Cordova Iceworm Festival in...
Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snowflake is a...
Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears. Learn more: USGS Water Science School - Glaciers: Things to Know
About 2.1% of all of Earth's water is frozen in glaciers. 97.2% is in the oceans and inland seas 2.1% is in glaciers 0.6% is in groundwater and soil moisture less than 1% is in the atmosphere less than 1% is in lakes and rivers less than 1% is in all living plants and animals. About three-quarters of Earth's freshwater is stored in glaciers. Therefore, glacier ice is the second largest reservoir...
Glaciers exist on every continent except Australia. Approximate distribution is: 91% in Antarctica 8% in Greenland Less than 0.5% in North America (about 0.1% in Alaska) 0.2% in Asia Less than 0.1% are in South America, Europe, Africa, New Zealand, and Indonesia.
Glaciers act as reservoirs of water that persist through summer. Continual melt from glaciers contributes water to the ecosystem throughout dry months, creating perennial stream habitat and a water source for plants and animals. The cold runoff from glaciers also affects downstream water temperatures. Many aquatic species in mountainous environments require cold water temperatures to survive. Some...
A path near the Mendenhall Glacier Visitor Center in Juneau, Alaska is completely submerged by floodwaters from a glacial lake outburst flood.
A path near the Mendenhall Glacier Visitor Center in Juneau, Alaska is completely submerged by floodwaters from a glacial lake outburst flood.
A new rift is forming across the Petermann Glacier. If this rift connects to existing rifts, it could result in another large iceberg breaking free.
At the USGS EROS Center, we study land change, operate the Landsat satellites, and maintain the longest, continuously acquired collection of images of the Earth's land surface.
A new rift is forming across the Petermann Glacier. If this rift connects to existing rifts, it could result in another large iceberg breaking free.
At the USGS EROS Center, we study land change, operate the Landsat satellites, and maintain the longest, continuously acquired collection of images of the Earth's land surface.
These Landsat 8 images show the latest iceberg to break free in Antarctica's Pine Island. Warmer ocean waters are melting the ice from beneath, causing increasing instability.
These Landsat 8 images show the latest iceberg to break free in Antarctica's Pine Island. Warmer ocean waters are melting the ice from beneath, causing increasing instability.
Grinnell Glacier Mather Overlook 2008 in color.
Grinnell Glacier Mather Overlook 2008 in color.
Monitoring glaciers in Glacier National Park.
Monitoring glaciers in Glacier National Park.
Located on the northwestern coast of Greenland, Petermann Glacier covers 1,295 square kilometers (500 square miles). The glacier's floating tongue of ice extends from the lower right corner of the image toward the top center. At 15–20 kilometers (9–12 miles) wide and 70 kilometers (43 miles) long, it is the longest floating glacier in the Northern Hemisphere.
Located on the northwestern coast of Greenland, Petermann Glacier covers 1,295 square kilometers (500 square miles). The glacier's floating tongue of ice extends from the lower right corner of the image toward the top center. At 15–20 kilometers (9–12 miles) wide and 70 kilometers (43 miles) long, it is the longest floating glacier in the Northern Hemisphere.
USGS scientist shoots a repeat photograph of Grinnell Glacier in Glacier National Park to illustrate glacial recession due to impacts of climate change.
*note – logo on scientists hat is logo from USGS Northern Rocky Mountain Science Center, not private.
USGS scientist shoots a repeat photograph of Grinnell Glacier in Glacier National Park to illustrate glacial recession due to impacts of climate change.
*note – logo on scientists hat is logo from USGS Northern Rocky Mountain Science Center, not private.
Glaciers are Earth's largest reservoir of freshwater. As they change, so does global sea level. Alaska has one of the largest accumulations of glaciers anywhere on Earth outside of the Polar regions. For most of the past half century, Alaska has experienced a significant increase in temperature that has profoundly impacted its glaciers. Join USGS scientist Dr.
Glaciers are Earth's largest reservoir of freshwater. As they change, so does global sea level. Alaska has one of the largest accumulations of glaciers anywhere on Earth outside of the Polar regions. For most of the past half century, Alaska has experienced a significant increase in temperature that has profoundly impacted its glaciers. Join USGS scientist Dr.
Surprise Glacier (in background), Harriman Fiord, western Prince William Sound.
Surprise Glacier (in background), Harriman Fiord, western Prince William Sound.
Barry Glacier, Barry Arm, western Prince William Sound.
Barry Glacier, Barry Arm, western Prince William Sound.
Photographer Tad Pfeffer capturing images of Columbia Glacier in Prince William Sound, Alaska. He is looking down-glacier towards the ice front, which faces open water in the fjord. This open water is extremely rare, and has not happened again since 2005. The fjord is typically covered with iceberg debris, called mélange.
Photographer Tad Pfeffer capturing images of Columbia Glacier in Prince William Sound, Alaska. He is looking down-glacier towards the ice front, which faces open water in the fjord. This open water is extremely rare, and has not happened again since 2005. The fjord is typically covered with iceberg debris, called mélange.
Peter Haeussler prepares to measure the offset of a crevasse on the Canwell Glacier.
Peter Haeussler prepares to measure the offset of a crevasse on the Canwell Glacier.
