Researchers have used data from the European Space Agency's CryoSat-2 satellite to identify a sudden drainage of large pools below West Antarctica's Thwaites glacier, the media reported.
Thwaites Glacier, already one of the planet's fastest-moving glaciers, is sliding unstoppably into the ocean, mainly due to warmer seawater lapping at its underside, speeding up by about 10 per cent from June 2013 and January 2014, Xinhua news agency reported.
In a study published in The Cryosphere, the researchers from the University of Washington (UW) and the UK's University of Edinburgh reported finding four interconnected lakes drained during the eight-month period.
"This was a big event, and it confirms that the long-term speed-up that we're observing for this glacier is probably driven by other factors, most likely in the ocean," said corresponding author Ben Smith, a glaciologist with the UW's Applied Physics Laboratory, on Sunday.
"The water flow at the bed is probably not controlling the speed."
The authors used a new technique to discover drops at the glacier's surface of up to 70 feet, over a 20 km by 40 km area.
Calculations show it was likely due to the emptying of four interconnected lakes far below. The peak drainage rate was about 240 cubic metres, per second, the largest melt-water outflow yet reported for subglacial lakes in this region.
The study supports previous UW research from 2014 showing that Thwaites glacier will likely collapse within 200 to 900 years to cause seas to rise by 2 feet.