[cogitator]

You might find this report interesting.

[JustDoItAlways]

What’s the temperature at the bottom of Greenland glaciers?

Won’t the water just refreeze at some point (unless it is close to the coast where it can escape to the ocean while the temperature of the water is still above Zero.)

[palmer]

held 0.044 cubic kilometers (11.6 billion gallons) of water...
The maximum drainage rate was faster than the average flow rate over Niagara Falls,

The flow over Niagra is 168000 m3 per minute or .168 km3 per minute. Most of the lake would have to have drained in 1/4 minute. Seems doubtful. The fracturing is interesting although not surprising. The question is how much the meltwater contributes to glacial flow. The answer is it does, but it isn't linear or simple. Here's an article with some details: http://www.nature.com/ngeo/journal/v1/n1/full/ngeo.2007.52.html

Basically they imply that the variations in the meltwater cause the most glacier motion (rather than the total volume).