How do ice islands differ from ordinary icebergs?

In the context of Arctic waters, ice islands serve as the functional equivalent of the classic tabular icebergs found in the Antarctic. While both are large masses of floating ice, they differ primarily in their physical dimensions and origins:1

• Dimensions: Ice islands are characterized by their tabular shape and significant surface area, reaching lengths of up to 30 km (19 miles). Despite this vast horizontal extent, they are relatively thin, typically measuring only about 60 metres (200 feet) in thickness.1
• Origin: Unlike many Arctic icebergs that originate from fast-flowing glaciers descending from the Greenland Ice Sheet, ice islands primarily calve from ice shelves, such as the former Ward Hunt Ice Shelf on Ellesmere Island or from ice caps like the Flade Isblink in northeastern Greenland.1

Because of their size and stability, some ice islands have historically been large enough to support manned scientific stations, such as the famous T-3 ice island.1