Мұз таулары: пайда болуы, түрлері және қауіптері

Large piece of freshwater ice broken off a glacier or ice shelf and floating in open water

An iceberg is a piece of freshwater ice more than 15 m long that has broken off a glacier or an ice shelf and is floating freely in open water. Smaller chunks of floating glacially derived ice are called "growlers" or "bergy bits". Much of an iceberg is below the water's surface, which led to the expression "tip of the iceberg" to illustrate a small part of a larger unseen issue. Icebergs are considered a serious maritime hazard. Icebergs vary considerably in size and shape. Icebergs that calve from glaciers in Greenland are often irregularly shaped while Antarctic ice shelves often produce large tabular (table top) icebergs. The largest iceberg in recent history, named B 15, was measured at nearly in 2000. The largest iceberg on record was an Antarctic tabular iceberg measuring sighted 150 mile (241 km) west of Scott Island, in the South Pacific Ocean, by the USS Glacier on November 12, 1956. This iceberg was larger than Belgium.

The word iceberg is a partial loan translation from the Dutch word ijsberg, literally meaning ice mountain, cognate to Danish isbjerg, German Eisberg, Low Saxon Iesbarg and Swedish isberg.

Air trapped in snow forms bubbles as the snow is compressed to form firn and then glacial ice. Icebergs can contain up to 10% air bubbles by volume.

An iceberg may flip, or capsize, as it melts and breaks apart, changing the center of gravity. Capsizing can occur shortly after calving when the iceberg is young and establishing balance. Icebergs are unpredictable and can capsize anytime and without warning. Large icebergs that break off from a glacier front and flip onto the glacier face can push the entire glacier backwards momentarily, producing 'glacial earthquakes' that generate as much energy as an atomic bomb.

Icebergs are generally white because they are covered in snow, but can be green, blue, yellow, black, striped, or even rainbow colored. Seawater, algae and lack of air bubbles in the ice can create diverse colors. Sediment can create the dirty black coloration present in some icebergs.

Prior to 1914 there was no system in place to track icebergs to guard ships against collisions despite fatal sinkings of ships by icebergs. In 1907, SS Kronprinz Wilhelm, a German liner, rammed an iceberg and suffered a crushed bow, but she was still able to complete her voyage. The advent of watertight compartmentalization in ship construction led designers to declare their ships "unsinkable". During the 1912 sinking of the Titanic, the iceberg that sank the Titanic killed more than 1,500 of its estimated 2,224 passengers and crew, seriously damaging the 'unsinkable' claim. For the remainder of the ice season of that year, the United States Navy patrolled the waters and monitored ice movements. In November 1913, the International Conference on the Safety of Life at Sea met in London to devise a more permanent system of observing icebergs. Within three months the participating maritime nations had formed the International Ice Patrol (IIP). The goal of the IIP was to collect data on meteorology and oceanography to measure currents, ice flow, ocean temperature, and salinity levels. They monitored iceberg dangers near the Grand Banks of Newfoundland and provided the "limits of all known ice" in that vicinity to the maritime community. The IIP published their first records in 1921, which allowed for a year by year comparison of iceberg movement.

Aerial surveillance of the seas in the early 1930s allowed for the development of charter systems that could accurately detail the ocean currents and iceberg locations. In 1945, experiments tested the effectiveness of radar in detecting icebergs. A decade later, oceanographic monitoring outposts were established for the purpose of collecting data; these outposts continue to serve in environmental study. A computer was first installed on a ship for the purpose of oceanographic monitoring in 1964, which allowed for a faster evaluation of data. By the 1970s, ice breaking ships were equipped with automatic transmissions of satellite photographs of ice in Antarctica. Systems for optical satellites had been developed but were still limited by weather conditions. In the 1980s, drifting buoys were used in Antarctic waters for oceanographic and climate research. They are equipped with sensors that measure ocean temperature and currents. Side looking airborne radar (SLAR) made it possible to acquire images regardless of weather conditions. On November 4, 1995, Canada launched RADARSAT 1. Developed by the Canadian Space Agency, it provides images of Earth for scientific and commercial purposes. This system was the first to use synthetic aperture radar (SAR), which sends microwave energy to the ocean surface and records the reflections to track icebergs. The European Space Agency launched ENVISAT (an observation satellite that orbits the Earth's poles) on March 1, 2002. ENVISAT employs advanced synthetic aperture radar (ASAR) technology, which can detect changes in surface height accurately. The Canadian Space Agency launched RADARSAT 2 in December 2007, which uses SAR and multi polarization modes and follows the same orbit path as RADARSAT 1.

In Labrador and Newfoundland, iceberg management plans have been developed to protect offshore installations from impacts with icebergs.

One of the most prominently known icebergs in recorded history is that which sank the Titanic on 15 April 1912. The catastrophe led to the establishment of an International Ice Patrol shortly after. Icebergs in both the northern and southern hemispheres have often been compared in size to multiples of the area of Manhattan Island. Artists have used icebergs as the subject matter for their paintings. Frederic Edwin Church, The Icebergs, 1861 was painted from sketches Church completed on a boat trip off Newfoundland and Labrador. Caspar David Friedrich, The Sea of Ice, 1823–1824 is polar landscape with an iceberg and ship wreck depicting the dangers of such conditions. William Bradford created detailed paintings of sailing ships set in arctic coasts and was fascinated by icebergs. Albert Bierstadt made studies on arctic trips aboard steamships in 1883 and 1884 that were the basis of his paintings of arctic scenes with colossal icebergs made in the studio.