The 2 principal types are valley glaciers and ice caps. Valley glacier movement is controlled by topography. Although velocity varies, most average less than a metre per day. However, some valley glaciers, called surging glaciers, can achieve speeds in excess of 60 m per day. Tens of thousands of valley glaciers now exist worldwide. In Canada they are found mainly at higher elevations of the western mountain systems and in the mountains and highlands of the arctic islands, eg, AXEL HEIBERG, ELLESMERE, DEVON and BAFFIN islands. Many are less than a kilometre long. Others are much longer, eg, the Hubbard Glacier in the Yukon and Alaska, which is over 100 km long.
ICE CAPS or ice sheets (if they are over 50 000 km2) are dome shaped and not greatly impeded by topography; thus, they are able to move outward in all directions. Generally, velocities of ice caps and ice sheets are lower than those of valley glaciers. Canada has several ice caps, located in the Cordillera and arctic islands.
Many features commonly produced by glaciers can be observed on or near the Athabasca Glacier in the Rocky Mountains of JASPER NATIONAL PARK. This glacier, fed by the COLUMBIA ICEFIELD, has been retreating for several years. Various features can be observed on the glacier surface, including crevasses, fissures that form from tensile stress in the glacier surface; icefalls, resulting from crevasses formed where the glacier hangs over a bedrock protuberance; and a medial MORAINE, composed of debris and ice, which is formed where 2 valley glaciers coalesce.
Other features that were formed during the retreat of the glacier (and can be seen nearby) include lateral and recessional moraines, formed by debris deposited along the glacier terminus. In addition, glacier meltwater carries and deposits debris, forming such features as deltas and glacial-outwash plains composed of sand and gravel.
See also GLACIATION.
Author N.W. RUTTER
Links to Other Sites
Centre for Earth Observation Science
Click on the interactive map to check out current CEOS scientific research projects. Many photographs and extensive technical data. A University of Manitoba website.
A definition of the term "cryosphere" from the "Climate and Cryosphere" website, a project of the World Climate Research Program. Browse other sections of this site for summaries of scientific research programs concerning cryosphere regions and their impact on global climate.
Axel Heiberg Haute Ski Traverse 2005
This site documents a skiing expedition that traversed Axel Heiberg Island in 2005. Check out the spetacular photos of island's icy landscape. From the Royal Canadian Geographical Society.
Journal of Glaciology
This site offers free access to selected articles from the "Journal of Glaciology." From the International Glaciological Society.
Learn about guided interpretive hikes onto the spectacular Athabasca Glacier located in the Columbia Icefield.
Glossary: Glacial Features
A glossary of terms that relate to glacial features. Check the rest of the site for additional information. From the Department of Earth Sciences, Simon Fraser University.
The World's Freshwater Map
Check out this interactive map of the world's freshwater resources. Depicts the geographical range of permafrost, glaciated areas, rivers and lakes, wetlands, and groundwater. From the National Geographic website.
Belcher Glacier: Time Lapse
Watch a video clip that shows changes in the surface of the Belcher Glacier through the warmest period of summer melt. Produced by the Canadian IPY: GLACIODYN Project. From YouTube.
View satellite images of the Llewellyn Glacier, an outlet glacier of the Juneau Icefield, located along the northern end of the Coast Mountains in British Columbia. From glacierchange.org.