Why do Arctic icebergs often have irregular shapes?

Arctic icebergs often exhibit irregular shapes due to the complex conditions surrounding their origin and subsequent environmental exposure. Unlike Antarctic tabular icebergs, Arctic bergs typically originate from fast-flowing glaciers that descend from the Greenland Ice Sheet. As these glaciers move through mountainous terrain, the irregular bedrock and valley walls create stresses that form crevasses, which are then incorporated into the structure of the resulting icebergs.1

Once formed, these icebergs contain inherent planes of weakness that lead to further fracturing. Their shapes are further altered by:

• Differential Melting: As icebergs drift, they experience varying melt rates at different depths depending on water temperature and salinity, which can cause the berg to lose stability and capsize.12
• Capsizing: Arctic icebergs frequently undergo repeated capsizes, which continuously change their orientation and expose new surfaces to erosion.2
• Surface Erosion: When icebergs are trapped in fjords, small convection cells at the ice-water interface can create scalloped indentations on their surfaces.1