SUITLAND, MD—— U.S. National Ice Center (USNIC), a U.S. Naval Meteorology and Oceanography command, confirmed iceberg A-74 (Fig. 1) split, or calved, into two icebergs—now identified as A-74A and A-74B—near Berkner Island in the Weddell Sea, June 7, 2022.

A-74A was centered at 76° 55′ South and 45° 54′ West , measuring 28 nautical miles on its longest axis and 18 nautical miles on its widest axis. A-74B was centered at 76° 45′ South and 44° 54′ West and measured 9 nautical miles on its longest axis and 4 nautical miles on its widest axis.

A-74 first calved from the Brunt Ice Shelf in March 2021 and has drifted 90 nautical miles westward in the 15 months since.

The calving event was first spotted by USNIC Analyst Katherine Quinn, and confirmed by USNIC Analyst Christopher Readinger using the Sentinel-1A image below.

Iceberg names are derived from the Antarctic quadrant where they are originally sighted.

Quadrants are divided counter-clockwise in the following manner:

A = 0-90W (Bellingshausen/Weddell Sea)

B = 90W-180 (Amundsen/Eastern Ross Sea)

C = 180-90E (Western Ross Sea/Wilkesland)

D = 90E-0 (Amery/Eastern Weddell Sea)

When first sighted, an iceberg’s point of origin is documented by USNIC. The letter of the quadrant, along with a sequential number, is assigned to the iceberg. For example, C-19 is sequentially the 19th iceberg tracked by USNIC in Antarctica between 180-90E (Quadrant C). Icebergs with letter suffixes have calved from already named icebergs, where the letters are added in sequential order. For example, C-19D is the 4th iceberg to calve off the original C-19 iceberg.

The U.S. National Ice Center is a multi-agency center operated by the Navy, NOAA, and Coast Guard and provides global to tactical scale ice and snow products, ice forecasting, and related environmental intelligence services for the United States government.

The U.S. National/Naval Ice Center is a subordinate command of U.S. Naval Meteorology and Oceanography Command that directs and oversees more than 2,500 globally-distributed military and civilian personnel who collect, process and exploit environmental information to assist Fleet and Joint Commanders in all warfare areas to make better decisions, based on assured environmental information, faster than the adversary.

Iceberg positions are analyzed weekly and are available on the USNIC webpage at:

https://usicecenter.gov/Products/AntarcIcebergs

For more information, please contact:

U.S. National Ice Center

Command Duty Officer

E-mail: [email protected]

Voice: (301) 943-6977

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