| This map shows the distribution of glaciers and
icefields in Canada, and also gives the names of some of their more
important individual bodies. The text below discusses the distribution
of these features, and then briefly comments on their impact on
the environment and on the population.
Glaciers and icefields are huge masses of ice. Generally, glaciers
flow in one direction, usually down a valley, while icefields and
their larger equivalents, icecaps, flow outward in many directions.
Glaciers and icefields cover about 10% of the earth's land area,
mainly in Antarctica and Kalaallit Nunaat (Greenland). In Canada,
an estimated area of 200 000 square kilometres, or about 2% of the
country's area is covered by glaciers and icefields.
A huge quantity of freshwater is frozen in polar ice caps and in
high mountain glaciers. Snow that is packed down over many years
at high elevations becomes glacial ice, which slowly proceeds downslope
like a frozen river, under the pull of gravity, and eventually melts
to become part of streamflow at lower elevations. If the rate of
melting is greater than the rate of accumulation, the glacier recedes;
if it is less, the glacier advances.
Distribution of Glaciers and Icefields
Although glaciers and icefields are only found in two regions of
Canada - the Western Cordillera and the mountains found in the eastern
Arctic - and they are very numerous and widely-distributed within
these areas. All ice features are remnants of the icefields of the
last ice age, which peaked about 18 000 years ago.
In western Canada, glaciers occur at much higher elevations in
the Rocky Mountains than in the wetter Coast Mountains. Mountain
glaciers carve out a variety of distinctive features such as bowl-shaped
features called cirques on the sides of mountains. The Arctic islands
contain many glaciers and also have many large icecaps. Ellesmere,
Baffin, Devon and Axel Heiberg islands contain huge icecaps which
range up to one kilometre thick.
Table 1 summarizes the extent of icefields and glaciers. At present
there are no reliable figures on either the total number of glaciers
in Canada. The National Hydrology Research Institute of Environment
Canada is in the process of identifying and measuring all glaciers.
Tables 1a and 1b show the best available estimates for areas by
region, and the number of glaciers for those areas surveyed to date.
Table 1a. Number and Area of Glaciers in Canada
Number and Area of Glaciers in Canada
| Axel Heiberg
Island |
11
380 |
1
121 |
| Baffin
Island |
35 900 |
10 224 |
| Bylot
Island |
4
850 |
575 |
| Coburg
Island |
220 |
92 |
| Devon
Island |
15
720 |
1
852 |
| Ellesmere
Island |
77
600 |
Data
not available |
| ice shelves
adjoining Ellesmere Island |
490 |
Data
not available |
| Meighen
Island |
80 |
Data
not available |
| Melville
Island |
150 |
Data
not available |
| North
Kent Island |
150 |
66 |
| Total
for Arctic islands |
146
540 |
Data
not available |
| Total
for Canada |
195
035 |
Data
not available |
|
Source: Canada. Environment Canada. National
Hydrology Research Institute. Ottawa, 1999.
Table 1b. Mainland Part of Canada: Glacier Data by Drainage Areas
Mainland Part of Canada: Glacier Data by Drainage Areas
| Nelson
River |
320 |
1
616 |
| Yukon
River |
10 250 |
Data not available |
| Great
Slave Lake |
600 |
Data
not available |
| Pacific
Ocean (other than Yukon River drainage) |
36
530 |
Data
not available |
| Arctic
Ocean (other than Great Slave Lake drainage) |
810 |
Data
not available |
| Atlantic
Ocean |
25 |
Data
not available |
| Total
for Canadian mainland |
48
535 |
Data
not available |
| Total
for Canada |
195
035 |
Data
not available |
|
Source: Canada. Environment Canada. National
Hydrology Research Institute. Ottawa, 1999.
Importance of Glaciers and Icefields
Glaciers exert a direct influence on the hydrologic cycle by slowing
the passage of water through the cycle. Like groundwater, glaciers
are excellent natural storehouses of water. One form of release
by glaciers is in sudden outburst floods called "jökullhaups".
Usually, the release is more gradual with glaciers having their
highest rate of melting in the summer. Glacier-fed rivers, which
include many of the largest rivers in Alberta and British Columbia,
reach their peak flow during hot summer weather when other sources
of water in these regions may be scarce. They are, therefore, extremely
important to the relatively dry Prairie region as sources of water
for irrigation, electric power, and uses by communities located
close to these rivers. |
