Iceberg D-33C Has Calved from Iceberg D-33B in the Weddell Sea

By LT Jacquelyn Putnam, NOAA
NIC.PAO@noaa.gov
U.S. National Ice Center
April 18, 2024

SUITLAND, MD — The U.S. National Ice Center (USNIC) has confirmed that iceberg D-33C (Ffigure 1, below) calved from iceberg D-33B in the Weddell Sea. As of April 14, D-33B was centered at 72°28' South and 18°58' West and measured 20 nautical miles on its longest axis and 7 nautical miles on its widest axis. D-33C was centered at 72°27' South and 18°36' West and measured 15 nautical miles on its longest axis and 7 nautical miles on its widest axis. The break was first seen on satellite imagery on April 14. D-33B first calved from the Borchgrevink Ice Shelf in August 2023.

The calving event was spotted by Dr. Klaus Strübing and confirmed by USNIC Analyst, Britney Fajardo, using the Sentinel-1A image 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 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.

Iceberg positions are analyzed weekly and are available on the USNIC webpage at: https://usicecenter.gov/Products/AntarcIcebergs

USNIC is a multi-agency center—subordinate to Naval Meteorology and Oceanography Command—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.

Naval Meteorology and Oceanography Command 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 faster than the adversary.

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