Glaciers appear when there is more snowfall than it melts every year. The snow collects, squeezing the lower layers hard. It turns to ice and forms a glacier. Glaciers appear only in cold climates where there is snowfall throughout the year. This is either in high latitudes i.e. the Arctic or Antarctic or at high altitudes i.e. in mountains. Glaciers first appear on the shady side of a mountain. There are more glaciers on the north-facing shady slopes of the Alps than on the sunny southern side. Most glaciers today are left over from the last Ice Age. In the last two million years there have been five glaciations. This the reason why glaciers appear. Due to the high pressure of ice, which is added every time due to which the crystals melt slightly and can slip easily. The rate of movement varies according to the slope of the valley, the thickness of the glacier, the roughness of the valley bottom and the temperature. Movement can be observed by putting a line of stakes across a glacier. The centre of the glacier moves faster than those at the side. The difference in the rate of movement creates huge gaps or crevasses within the glacier. Rocks and stones (moraine) fall on to a glacier and are picked up by the ice at the bottom of a glacier.
Out of the world’s 10 longest glaciers, eight are in Antarctica. Lambert-Fisher Ice Passage is the longest, which has a total length of 515 kilometers. In the northern hemisphere, Petermanns Glacier in Greenland is the largest glacier, which extends 40 kilometers out to sea. The largest glaciers are fed with ice from the great ice sheets covering Antarctica and Greenland. Greenland has the fastest-moving glacier the Quarayaq advances at 2024 meters a day.
Spectacular glaciers are found elsewhere in the world. The longest Himalayan glacier is the Siachen (76 kilometers long) in the Karakoram Range. Among the world's twenty longest glaciers are those in North America (in Alaska), Asia (in the Pamirs), in New Zealand and in the Alps. You feel like heaven when you see these spectacular glaciers.
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