Pine Island Glacier in Antarctica has snapped off its share of icebergs in recent years. The frequency of noteworthy breaks is evidence that the ice shelf is becoming increasingly fragile. The latest iceberg cracked off the end of the Pine Island Glacier ice shelf around September 23, 2017.

Named B-44, the new iceberg covers 71.5 square miles according to the U.S. National Ice Center. B-44 is likely to remain in place until the sea ice breaks up later in the Antarctic summer. It will then drift into Pine Island Bay. Landsat 8 images one week apart in September 2017 show the iceberg separating from the end of the ice shelf and even splitting into smaller pieces.

A much smaller iceberg broke off in January 2017. Other substantial breaks happened in 2013, 2014, and 2015. As Pine Island Glacier continues thinning and retreating, more inland ice will be allowed to flow to the ocean, contributing to sea level rise.

The dark spot seen in this pair of images is open water, called a polynya. They form where relatively warmer ocean water rises to the surface.

A cavity underneath the ice shelf, which likely formed in the 1940s, has been allowing streams of relatively warm ocean water to melt it from underneath.