What Is A Valley Glacier

Valley Glaciers

Valley glaciers

Valley glaciers are streams of flowing ice that are bars within steep walled valleys, often following the course of an ancient river valley. The downwardly erosive action of the ice carves the valley into a broad U shape, in contrast to the steeper 5 shape that is produced during the early on stages of erosion by rivers. A U shape valley with a flat floor is good testify of the past glaciation of an area.

U shaped valley with flat floor in the European Alps

Valley glaciers commonly outset life in either corries or ice sheets. Glacial ice flowing down colina from either of these sources will follow any existing valleys or easy routes, eroding and enlarging them every bit it moves.
Ofttimes several corrie glaciers will combine to feed a single valley glacier. In the photograph below, iii small corries are feeding a small valley glacier

Three corries contributing to a valley glacier

Three corries feeding a valley glacier in a hanging valley

In large systems, valley glaciers may join and grade larger glaciers with much greater erosional ability than they had as smaller individuals. As the master glacier erodes its valley downwardly more than speedily than surrounding valleys, they are left backside, finally condign hanging valleys.

Stone debris falls from the steep valley walls and litters the glacier surface. This occurs specially along the edges, where rock debris builds up and is known equally lateral moraine. Where ii glaciers see and menstruum into each other, the ii edges where the coming together occurs become the eye of the new glacier. The two lateral moraines combine to grade a medial moraine.

Valley glacier showing medial and lateral moraines. The medial moraine originates where the two valleys join in the background.

From the glacier snout, meltwater flows downwardly the valley within braided river systems. Vast quantities of eroded material are transported by these fast flowing streams. Material moved abroad from the glacier in this way is called fluvioglacial, distinguishing it from material deposited at the site of the glacier. Deposits left in situ past retreating glaciers are chosen till deposits.

Braided glacial streams are unstable, frequently altering their course and bed shape. In wintertime, when they and their glacial source freeze, they may stop flowing. During the leap thaw and hot summer they may become raging torrents capable of moving rocks the size of family cars!

Braided glacial stream in summertime

The tendency of braided streams to change course is not a trouble in wilderness areas, just could represent a serious hazard if it occurred within an inhabited locality. To protect villages and towns, potentially dangerous streams are often diverted forth courses lined with thick concrete or rock walls. Regular dredging removes the larger boulders and deposits of silt, whilst the strong walls confine the water fifty-fifty nether flood conditions.

Glacial outwash stream confined by concrete and rock walls as it enters the boondocks of Chamonix, French republic. The fog is caused past the icy h2o from the high glaciers flowing through the much warmer air in the lower valley