The sheer scale of B-15A is best appreciated from space. The bottle-shaped Antarctic iceberg is around 120 kilometres long, with an area exceeding 2500 square kilometres, making it about as large as the entire country of Luxembourg. Back in Janauary the iceberg appeared to be drifting towards the 70-kilometre-long Drygalski ice tongue in McMurdo Sound on the Ross Sea, and an unprecedented ice collision looked imminent.
However B-15A eventually slowed down and stopped. Local bathymetry charts suggested the iceberg had become anchored at a point near the middle of its coastward (or western) side to a shallow section of seabed.
In early March local tides and currents lifted B-15A free from its temporary resting place, an event coinciding with numerous fragments of ice seen breaking off from the centre of its coastward side as the iceberg was worked loose.
Now prevailing currents are transporting it into deeper and out of McMurdo Sound, right past the far end of the Drygalski ice tongue. The latest Envisat satellite image shows the two ice masses only a few kilometres apart.
Mark Drinkwater of ESA's Ice/Oceans Unit is among researchers keeping close watch on the situation: "The widest part of the iceberg would now appear to have successfully negotiated the narrow channel between the shallow seamount to its west where it was formerly grounded and Franklin Island to the east.
"It was now achieved a critical overlap with the end of the Drygalski ice pier, so far without touching. It would now appear that any contact if at all between the drifting iceberg and the land-fast floating ice tongue is likely to be a consequence of being 'brushe
Contact: Mariangela D'Acunto
European Space Agency