Iceberg and glacier 'on a collision course'

Scientists were watching on Monday for a collision between a giant iceberg and an Antarctic glacier, which could free up sea lanes to America's McMurdo Station and help penguins reach crucial feeding areas.

The iceberg B15-A, which is about 160km long and contains enough drinking water to supply the world for several months, was once part of the major B15 iceberg which broke off the Ross Ice Shelf on the edge of Antarctica five years ago.

B15-A has been drifting slowly towards the floating end of a glacier known as the Drygalski Glacier Tongue for several months and scientists now believe a collision is likely.

"It seems highly likely, given how this thing has jiggled around for the past four years," Australian Antarctic scientist Neal Young said.

The United States National Science Foundation (NSF) had predicted the collision would occur before Christmas, while the space agency NASA suggested the crash would happen by January 15.

But Young, from the Antarctic Climate and Ecosystem Co-operative Research Centre, on Monday said the iceberg was still about 4,8km from the Drygalski Glacier Tongue and was moving about 1,6km a day.

He said while a collision was likely, it might not happen as storms and sea currents could change the iceberg's course.

"There is no guarantee there will be any collision, or it could be catastrophic in terms of having quite big consequences," he said.

He said a collision could lop a large chunk off the iceberg and allow it to drift out of the area around Ross Island, making it easier for icebreakers to reach McMurdo Station. New Zealand also has a base in the area.

He said it would also give penguins a shorter trip to the sea to find food for their young and would help boost local penguin populations.

"If B15-A does eventually does escape then I think it is likely the whole area will open up again, in that it has been a real barrier up until now," he said.

But a collision could also knock off a piece of the Drygalski Glacier Tongue, which could lead to more ice in the sea routes toward the Italian research base at Mario Zucchelli Station.

The NSF has said the iceberg posed no threats to supplies or personnel at McMurdo Station.

Young, who is monitoring the iceberg through Nasa and European Space Agency satellite images, said the last known chunk to be carved off the Drygalski Glacier Tongue occurred in 1956.

Scientists were now eagerly watching to see what would happen if the iceberg and glacier collide.

"This is the biggest thing we've seen for a while," he said.