Iceberg B-15AC Calves off of B-15T as it drifts in the warmer Southern Ocean

By LTJG Bryan R. Brasher, NOAA
U.S. National Ice Center
January 25, 2019

Suitland, MD — The U.S. National Ice Center (USNIC) named a new iceberg that calved from the previously named B-15T iceberg in the south Atlantic Ocean 340 NM east of South Georgia Island. Over the past few months as B-15T has drifted in warmer ocean water it is breaking up causing this calving event.

B-15AC is located at 548’South, 2618’West in the south Atlantic Ocean. The iceberg measures 12 nautical miles on its longest axis and 3 nautical miles on its widest axis. Analyst Chris Readinger confirmed iceberg B-15AC using the MODIS image shown below.

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.

MODIS image of Iceberg B-15AC
Figure 1: MODIS image of B-15AC dated January 23, 2019

For more information, please contact:
National Ice Center
Command Duty Officer
Voice: (301) 943-6977
Twitter: @usnatice
Facebook: @usnatice

The U.S. National Ice Center is a tri-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.

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