Icebergs: Origins and Ocean Drift

Origin: Icebergs calve from glaciers (land-based ice) or ice shelves (floating extensions) when they reach the sea. Triggers include:

• Calving from thinning or stressed ice fronts.
• Melting in warmer water causing instability.
• Wave and tidal erosion.

Drift: Icebergs float because ice is less dense than seawater. They are transported by ocean currents, sometimes traveling thousands of kilometers. Some enter the Antarctic Circumpolar Current and become trapped in pack ice.

Hazard: Icebergs threaten shipping; the RMS Titanic (1912) is the most famous disaster.