- 89 x 14 nautical miles dimension(s)
- Antarctica ()
The record for the largest current iceberg changed hands on 13 May 2021 when a large tabular iceberg detached from the western part of the Ronne Ice Shelf in Antarctica into the Weddell Sea. The new iceberg – named A-76 – was measured using satellite imagery at around 165 kilometres (89 nautical miles) long and 26 kilometres (14 nautical miles) wide, with an estimated total area of 4,320 square kilometres (1,670 square miles).
This made it larger than the previous record holder, the c. 4,000-km2 (1,545-sq-mi) A-23A, which had only held the record for a few months since December 2020. Also located in the Weddell Sea, A-23A was calved from the Filchner Ice Sheet in August 1986, but has only moved around 200 km (125 mi) in 30-plus years because it is grounded on the sea floor.
The process by which icebergs break off from the Antarctic Ice Sheet is known as "calving" and this is usually part of a natural cycle. When glaciers flow off the continent, they begin to float and spread across the ocean surface. The winds and tides can then cause cracks to appear and new icebergs are born. The birth of A-76 is therefore not necessarily linked to climate change, but scientists are continuing to monitor Antarctica to see if these calving events are becoming more frequent as the air and ocean temperatures increase.
The largest iceberg ever reliably documented was approximately 31,000 km2 (12,000 sq mi) – making it larger than Belgium. It was 335 km (208 mi) long and 97 km (60 mi) wide and was sighted 240 km (150 mi) west of Scott Island, in the Southern Ocean by the USS Glacier on 12 November 1956. The precise extent of the iceberg witnessed by the crew of the Glacier was estimated, as they did not have the benefit of satellite photography.