In late September, 2019, a large iceberg calved from the Amery Ice shelf. The iceberg, named D28, measured about 30 km (18.6 mi) wide and 60 km (37.3 mi) long, or roughly the same area spanned by the city of Houston. The thickness was estimated to be more than 200 m (656 feet) thick, making it likely the iceberg contains over 330 billion tons of ice. Since calving, the iceberg has slowly drifted away from the shelf where it was born.
On March 19, 2020, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of Iceberg D28 floating in the waters off of the Amery Ice Shelf.
For ice shelves and for glaciers that touch the ocean, calving is part of the natural cycle of advance and retreat. Compared to melting, the fastest way for glaciers to lose mass to the ocean is through rifting and the subsequent calving of icebergs. The Amery Ice Shelf, located in East Antarctica, is considered a fairly stable shelf. This calving was the first major iceberg in more than half a century.