Glacial lake transformed to titanic torrent
WASHINGTON (AP) - April 17, 2008 A meltwater lake on the surface of a glacier suddenly emptied in
July 2006, sending millions of gallons of water through cracks in
the ice sheet to the ground where it could affect the movement of
the ice.
The lake covered 2.2 square miles near the western edge of the
ice sheet and took about 24 hours to drain.
During the most rapid 90 minutes, water was flowing out of the
lake at 2.3 million gallons per second, according to researchers
led by Sarah Das of Woods Hole Oceanographic Institute in Woods
Hole, Mass.
Under international convention, the minimum flow of Niagara
Falls in summer is about 750,000 gallons per second.
The findings are reported in a pair of papers about the
Greenland ice sheet appearing in Thursday's online edition of the
journal Science. Das and Ian Joughin of the University of
Washington in Seattle led the teams that produced both papers.
"We found clear evidence that supraglacial lakes - the pools of
meltwater that form on the surface in summer - can actually drive a
crack through the ice sheet," Das said in a statement.
The researchers concluded that while surface melt plays a
significant role in overall ice sheet dynamics, it has less of an
effect than had been expected on the fast-moving glaciers that
discharge ice to the ocean.
The research was funded by the U.S. National Science Foundation,
NASA, Woods Hole Oceanographic Institute, Clark Arctic Research
Initiative and the Natural Environment Research Council of Britain.
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