The lake that Sarah Das and her fellow scientists were camping near suddenly started to vanish last weekend.
"At one point we heard really loud cracks and booms from across the lake and then the water line disappeared," said Das, who grew up in Squirrel Hill and is now a glaciologist with the Woods Hole Oceanographic Institute in Massachusetts. "The ground started to creak and crackle beneath our feet."
Das is spending two weeks camping on the western edge of Greenland's 2-mile-thick ice sheet. She is co-leading three other scientists on a two-week expedition to study lakes that form on the ice sheet in the summer. On Friday she answered questions from Carnegie Museum of Natural History visitors via a live satellite call.
The call was part of a public outreach program paid for by the Richard King Mellon Foundation and the National Science Foundation. The goal is to teach people about ongoing studies of the world's ice sheets and the impact climate change is having on them.
At 2:15 p.m. today, another call will be placed to the scientists from the museum's Earth Theater. Visitors are welcome to participate.
Mary-Louise Timmermans, an Arctic physical oceanographer with the institute, hosted yesterday's call.
"Greenland is the world's largest island and 80 percent of it is covered with ice," Timmermans told about 65 visitors.
In the summer it is warm enough for some ice to melt, forming glacial lakes that can grow as large as Lake Arthur in Moraine State Park. As the lakes become larger, the weight of the water causes cracks in the ice below. These cracks eventually reach the bedrock below the ice sheet. When this happens the lakes suddenly drain away, flow under the ice sheet and into the ocean.
"The water drains out at the speed of Niagara Falls," Timmermans said.
Scientists suspect that the water acts as a lubricant between the ice sheet and the bedrock, carrying the ice into the ocean. They are studying the process because rising global temperatures could cause more lakes and cracks to form, which would accelerate the flow of ice to the sea.
Soon Das' team will pour dye into one crack to track how long it takes the water to reach the ocean.
Connor Monzo, 10, of Greensburg begged his mother, Lisa, and sister, Megan, 8, to attend the call. He wants to be a glaciologist.
"I think Greenland is a very interesting (place)," Connor said. "I think it would be really neat to go there and study it."
He'd better prepare for some extreme living, Das said.
Each scientist has a bright orange tent. During the day the intense sun heats the tents to nearly 100 degrees, but at night the temperature dips to below freezing.
The sun reflects off the ice with such strength that it burns the inside of the scientists' nostrils. And there are no showers.
But Das isn't complaining.
"I love my job," she said. "It's a lot of fun to come up here and do the field work and make a contribution to such a big thing."
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