Located in the northwest corner of Greenland, Leidy Glacier is fed by ice from the Academy Glacier (upstream and inland). As Leidy approaches the sea, it is diverted around the tip of an island that separates the Olriks Fjord to the south and Academy Cove to the north. The resulting crisscross pattern is simply the result of ice flowing along the path of least resistance.
This view of the region pictured above was acquired August 7, 2012, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. In April 2012, the feature caught the attention of NASA pilot Donald "Stu" Broce, who snapped the picture below from the cockpit of a high-flying ER-2 aircraft during a research flight over the Greenland ice cap. Snow that blanketed the rocky outcrops in springtime had melted by summer.
Researchers have found that the small glaciers in the area of Leidy Glacier did not change much between the winters of 2000 and 2005. That's in contrast to the Tracy and Heilprin glaciers just north of Leidy, which sped up by 40 percent and 18 percent, respectively, during the same study period.
Loss of ice to the ocean through glaciers is not the only way Greenland is losing mass. According to research published in January 2015, rivers of glacial meltwater flowing over Greenland's frozen surface may be contributing as much to global sea level rise as all other processes that drain water from the melting ice sheet combined.
NASA Earth Observatory image (top) by Jesse Allen, using data from NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Photograph (bottom) by Donald Broce. Caption by Kathryn Hansen.
On Greenland, tens of thousands of years of snowfall have settled and solidified into a massive sheet of ice. Each summer, snow retreats briefly at low elevations, and a narrow strip of rocky coastline emerges. While some seasonal thawing is typical on Greenland, more dramatic changes are probably in store for the Greenland Ice Sheet in coming decades and centuries.