An iceberg is a large piece of ice that has broken off from a glacier or an ice shelf and is floating in open water. A typical iceberg is about 20 meters (66 feet) high and weighs about 200,000 metric tons (220,000 short tons).
Icebergs are found in all the world’s oceans, but most occur in the Southern Ocean around Antarctica. The largest iceberg on record was approximately 5800 cubic kilometers (1400 cubic miles) and was calved from the Ross Ice Shelf in 2000.
Most icebergs are formed when chunks of ice break away from glaciers or ice shelves due to the effects of wind, wave action, or thermal expansion and contraction. These events are called calving. Once an iceberg has calved, it begins to drift with ocean currents and eventually melts as it moves north into warmer waters.
The rate at which an iceberg melts depends on its size, shape, composition, and the ambient air and water temperatures. For example, a small iceberg melting in warm water will melt much faster than a large one melting in cold water. Similarly, an irregularly shaped iceberg will melt more quickly than one with a smooth surface because it has more surface area exposed to the warming effects of sun and waves.