Not every chunk of floating ice is an iceberg. An iceberg is ice that has broken off a glacier or an ice shelf and floats in open water — but only if it is big enough. Smaller pieces have their own, more playful names: bergy bits and growlers.
An iceberg in the Ross Sea, Antarctica. Credit: NOAA.
Sorting ice by size
| Type | Height above sea level | Size |
|---|---|---|
| Iceberg | more than 16 feet, with a thickness of 98-164 feet | covers at least 5,382 square feet |
| Bergy bit | generally more than three feet but less than 16 feet | normally about 1,076-3,229 square feet |
| Growler | less than three feet | about 215 square feet — roughly the size of a truck or a grand piano |
Bergy bits and growlers can come from glaciers or ice shelves, or from a large iceberg that has broken apart.
Sorting ice by shape
Icebergs are also classified by shape, most often as one of two kinds:
- Tabular icebergs have steep sides and a flat top.
- Non-tabular icebergs take other shapes, with domes and spires.
Who keeps track
The U.S. National Ice Center (NIC) monitors icebergs around the world. It produces analyses and forecasts of ice conditions in the Arctic, the Antarctic, the Great Lakes and Chesapeake Bay — and it is the only organization that names and tracks all Antarctic icebergs.
Sources
Based on "What is an iceberg?" from NOAA's National Ocean Service, a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from oceanservice.noaa.gov
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