NASA released a new image of Antarctica’s Brunt Ice Shelf this week as they are thoroughly monitoring a series of cracks in it and preparing for the break-off of an iceberg approximately 30 times the size of Manhattan – the area is estimated to be 1,700 sq. km.
Satellite images captured on 23 January reveal a rift along the top of the image – known as Halloween crack – that first appeared in late October 2016, which has since been extending eastward from an area known as the McDonald Ice Rumples.
“The near-term future of Brunt Ice Shelf likely depends on where the existing rifts merge relative to the McDonald Ice Rumples. If they merge upstream (south) of the McDonald Ice Rumples, then it’s possible that the ice shelf will be destabilised”, said Joe MacGregor, a glaciologist at NASA’s Goddard Space Flight Centre.
Another crack in the centre of the image was stable for some 35 years, but has recently started accelerating northward, growing up to 4 kilometres per year.
While it remains unclear how events are going to unfold, the cracks growing at staggering rates have prompted safety concerns for people working on the shelf, namely researchers at the British Antarctic Survey’s Halley Station. NASA has emphasised that the calving effect was a normal part of the “life cycle of ice shelves, but the recent changes are unfamiliar in this area”.
“We don’t have a clear picture of what drives the shelf’s periods of advance and retreat through calving. The likely future loss of the ice on the other side of the Halloween Crack suggests that more instability is possible, with associated risk to Halley VIa”, NASA/UMBC glaciologist Chris Shuman said.