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#PRTO_Iceberg
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^An iceberg is a large piece of freshwater ice that has broken off from a snow-formed glacier or ice shelf and is floating in open water. It may subsequently become frozen into pack ice or come to rest on the seabed in shallower water, causing ice scour. 
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#DESC_PRTO_Iceberg
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^Because the density of pure ice is about 920 kg/m, and that of sea water about 1025 kg/m, typically only one-tenth of the volume of an iceberg is above water.
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^Icebergs generally range from 1 to 75 meters (3250 ft) above sea level and weigh 100,000 to 200 000 tons. The tallest known iceberg in the North Atlantic was 168 meters (550 ft) above sea level, making it the height of a 55-story building. Despite their size, the icebergs of Newfoundland move an average of 17 kilometers a day (10 mi).These icebergs originate from the glaciers of western Greenland, and may have an interior temperature of -15 to -20C (5 to -4 F).
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^Though usually confined by winds and currents to move close to the coast, the largest icebergs recorded are calved, or broken off from, the Ross Ice Shelf of Antarctica. Iceberg B-15, photographed by satellite in 2000, measured 295 km long and 37 km wide (183-23 mi), with a surface area of 11,000 km (4,250 mi). The mass was estimated around three billion tonnes.
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^There was no system in place before 1912 to track icebergs to guard against ship collisions. The sinking of the RMS Titanic, which caused the death of more than 1,500 of its 2,223 passengers, created the demand for a system to observe icebergs. For the remainder of the ice season of that year, the United States Navy patrolled the waters and monitored ice flow. 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).
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^Details from Wikipedia.
