Category Social Sciences

Where does most snow fall?

Snow can fall wherever the weather is very cold, and it falls throughout the year in the Arctic and Antarctic.

Most snow falls in temperate climates during the winter, especially in the Alps in Italy and Switzerland and in the Rocky Mountains in the USA. In fact, almost every mountain range is associated with heavy snowfalls. Snow can even fall on the Equator on mountains more than 4,880 m high, where the air is very cold. 

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How thick is the ice at the South Pole?

The thickest ice at the South Pole is 4,800 m deep — that’s ten times the height of a tall skyscraper. The ice covers a huge area of 14 million sq km, which is bigger than the whole of Europe. However, the land area under the ice is much smaller because the ice sheet extends out over the sea. Antarctica contains 90 percent of all the ice on the Earth. Scientists have calculated that should all this ice melt sea levels would rise by 60 m causing world-wide flooding.

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How does frost break up rocks?

Frost can shatter rocks, making it one of the most important causes of erosion in cold regions. Water seeps into small cracks in rocks and freezes at night, when frost appears. As water freezes it expands slightly, opening up cracks in the rock until parts of it flake away. This process continues until large masses of rock are broken up. It is the cause of the piles of shattered rock, or scree that are commonly found at the foot of mountains. You can see the same process at work when a clay flowerpot left in the garden in winter begins to flake and crack. 

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Why do icebergs float?

Ice floats because it is lighter than water. Most objects shrink when they get cold, but when water freezes it expands slightly. In this way ice becomes lighter than water. It is only slightly lighter however, and so nine-tenths of a floating iceberg lies under the water. 

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Frozen

Glaciers and ice sheets sometimes give up their secrets centuries later. Thawing ice has revealed the bodies of people who fell into crevasses hundreds of years ago. The ice has preserved their clothes and their internal organs. Even more astonishing are the bodies of mammoths found occasionally in the permafrost under Alaska and Siberia. Scientists are trying to extract their DNA so they can study these extinct beasts in minute detail. 

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How big are icebergs?

Some icebergs are bigger than an entire country. The biggest iceberg ever recorded was larger than Belgium, with an area of 31,000 sq km. These giant icebergs break away from the polar ice sheets when the rise and fall of the tide crack the ice. 

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Is there such a thing as red snow?

Red snow is found in many parts of the world, when tiny plants grow over the snow and ice. Microscopic algae growing on the surface of snow and ice can give them a red colour. This rare event happens when the weather warms up slightly, and the algae that have been dormant throughout the cold period suddenly start to grow again. 

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What are glaciers?

Glaciers are large masses of ice that form on land and move slowly under their own weight. They are found in cold mountainous places or Polar Regions. Some glaciers are huge continuous sheets of ice, such as those covering Antarctica and Greenland. But most are rivers of ice that move slowly through valleys until they melt and become rivers. Such glaciers are common in the Himalayas, Alps and Rocky Mountains. Because of its enormous weight a glacier scrapes off large amounts of rock and debris, wearing away the valley floor and sides until it carves out a deep ‘U-shaped’ valley. Glaciers formed the deep fjords that line the coast of Norway.

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Why does snow fall?

Snow forms when water vapour inside a cloud freezes into tiny crystals. The water vapour usually crystallizes around a tiny dust particle called a nucleus, and the snow crystal continues to grow. Crystals of snow clump together to form snowflakes, which fall from the clouds. As many as 100 snow crystals group together to form a 2.5 cm snowflake. Snow crystals are very beautiful in form. They are flat and six-sided, and can grow in the shape of elaborate stars. 

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What is the snow line?

The snow line marks out the area above which a mountain is permanently covered with snow. Because it gets colder as you move higher up, the snow will never thaw on a high mountain. However, the snow line moves higher up during the summer when some of the snow melts. The snow line is close to ground level in cold regions, but it is very high near the Equator where the air is much warmer. 

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