How Fast Does the Ice Flow?
What the researchers really want to know is how all this meltwater affects the flow of the broader ice sheet once it gets to the bedrock below. “It’s kind of hard to say what the impact one particular lake would have on the velocity of a large portion of the ice sheet,” Das says. “But in general, it would seem that the ice sheet is speeding up quite a bit.” To figure out just how much faster the ice is flowing, Das and Joughin set up instruments to measure the ice’s movement. Now, nine months later, they’re getting some answers. The results are published online in Science Magazine. One of the most dramatic findings is that these temporary lakes can be really temporary. “One of the lakes we were monitoring was about two miles wide and 40 feet deep, and it drained in the space of about 90 minutes, with flow greater than the flow over Niagara Falls,” says Joughin. So much water flowed under the ice, it actually lifted the glacier by three feet and sent it slip-sliding a bit toward the coa
