Friday, April 18, 2008

Glacier Lake vanishes into 'Niagra Falls'

What used to be a glacier, will just be ice floating down the river.
clipped from www.abc.net.au

Glaciologists have documented for the first time the sudden disappearance of a lake on the top of the Greenland ice sheet, which they say drained away with the force of Niagara Falls.

glacier melt stream
Like bathwater rushing down a plug-hole, the vast lake of meltwater vanished in a day through a crack in the ice, say researchers
A lake of meltwater on the surface of a glacier connects to a channel that will eventually take the water to the glacier bed (Science)
A lake of meltwater on the surface of a glacier connects to a channel that will eventually take the water to the glacier bed
A large opening in the drained lake bed (Science)
A large opening in the drained lake bed

The research documents a natural plumbing system on the glacier which enabled meltwater to gush through a kilometre-thick ice mass and reach its base, a phenomenon that scientists believe can help speed up summer ice movement.

Das and colleagues say the maximum drainage rate of the 5.6 square kilometre lake was faster than the average flow rate over Niagara Falls.

Like a draining bathtub, the entire lake emptied from the bottom in 24 hours, with the majority of the water flowing out in a 90-minute span, they say.

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