Iceberg A-69 breaks becoming Icebergs A-69A and A-69B in the Weddell Sea

By LT Falon M. Essary, USN
U.S. National Ice Center
July 07, 2020

Suitland, MD — The U.S. National Ice Center (USNIC) confirmed that the newly named iceberg A-69 has broken into two nameable icebergs. A-69A is located at 69°01’ South, 60°34’ West, in the Weddell Sea, it measures 10 nautical miles on its longest axis and 9 nautical miles on its widest axis. Iceberg A-69B is located at 68°52’ South, 60°41’ West, in the Weddell Sea, it measures 10 nautical miles on its longest axis and 7 nautical miles on its widest axis. A-69A and A-69B were confirmed by USNIC Master Ice Analyst Chris Readinger using the Sentinel-1A images.

Iceberg names are derived from the Antarctic quadrant in which they were originally sighted. The 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 the 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 the 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 National Ice Center is a tri-agency operational center represented by the United States Navy (Department of Defense), the National Oceanic and Atmospheric Administration (Department of Commerce), and the United States Coast Guard (Department of Homeland Security). The National Ice Center mission is to provide the highest quality strategic and tactical ice services tailored to meet the operational requirements of U.S. national interests and to provide specialized meteorological and oceanographic services to United States government agencies.

Satellite image of Iceberg A-69A and A-69B
Figure 1: SENTINEL-1A image from 05 July (2359Z) showing both A-69A and A-69B. (Sentinel-1 Imagery courtesy of European Space Agency)

For more information, please contact:
National Ice Center
Naval Ice Center
Command Duty Officer
Voice: (301) 943-6977
E-mail: nic.cdo@noaa.gov
Twitter: @usnatice
Facebook: @usnatice

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