Big Ice

Greenland Lakes 2010

In July 2010 a team from the University of Washington (Ian Joughin and Kristin Poinar) and the Woods Hole Oceanographic Institution (Sarah Das and Mark Behn) returned to the North and South lake sites to reinstall GPS, seismic, and other instruments to monitor lake drainages and ice flow variability. Since the instrument towers were subject to two years of melt (~1.5 meters or 5 feet each year), they had to be taken down and fully rebuilt. This was a bridge year and in Summer 2011 a new project will begin with a more extensive network of GPS around the lakes to study the processes by which water can hydro-fracture to the bed through ice more than a kilometer (.62 miles) thick.

The lake just to the north of North Lake, North-North Lake, had not drained the previous summer when its spectacular drainage channel was dammed with snow. As a result, North-North lake contained one and half seasons of melt water. North Lake had drained but the crack did not run directly through the deepest parts of the lake, so the lake was still partially full. Unlike the the previous two summers, but similar to other years, the South Lake drained over its side to a moulin some distance away.



Former North-North Lake Drainage Channel
For several years this channel drained water from the north-north lake to a moulin in a nearby crevasse field. It has since filled with snow, which has dammed it shut. As a result, the lake did not drain in 2009 and it was still full as of early July 2010.

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