Within a week of breaking away from the Pine Island Glacier, the newly calved Iceberg B-31 was putting some distance between itself and the calving front where it was born. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured this true-color image on November 18, 2013.
The iceberg broke away from Pine Island Glacier between November 9 and 11, 2013. The calving event was not unexpected, since scientists first noticed a rift in the glacier nearly two years previously, in October 2011, during flights for Operation IceBridge. By July 2013 infrared and radar images indicated that the crack had completely breached the calving front.
The gap between the Singapore-sized iceberg and the glacier has widened rapidly since November 11. This seemingly vigorous motion may seem to suggest that the berg is on its way to open ocean – but its route is far from certain. According to NASA glaciologist Kelly Brunt, it is hard to predict where and when icebergs might drift. Speculation is that if Pine Island Bay clears of ice by the annual sea ice minimum in February- March, then Iceberg B-31 could move onto the open Southern Ocean, drifting southward on prevailing currents.
What happens after than depends more on the shape of the iceberg than anything else. Researchers have found that larger icebergs with deeper keels tend to drift with the deeper, cyclonic circumpolar current, while sea ice and smaller bergs with shallower keeps tend to drift with the coastal counter current.