Live From the Poles: North Lake and the Journey Home

Our guest blogger today is Chris Linder, a Research Associate at the Woods Hole Oceanographic Institution in Massachusetts. He is the project manager and field photographer for the National Science Foundation-sponsored Live from the Poles project. He’s been sending us weekly updates about their progress.

On July 21, scouts, summer campers and Ecoteens had a chance to get their most pressing climate questions answered from Ian Joughin, the leader of the Greenland Glacier Expedition that Chris has been writing about here through a live satellite link to the campsite in Greenland; later that night, adults got their turn. You can listen in, below.


The team is now back from the Greenland; here’s Chris’ last post on what they learned.

North Lake and the Journey Home

It has been a whirlwind since my last post—a hectic final week on the Greenland ice sheet studying two glacial lakes, a helicopter transfer back to the town of Ilulissat, and a long series of flights taking us home. Warm socks and down jackets are now a thing of the past—I’m typing this dispatch in 87-degree heat in Seattle (I know that’s not really hot for Texans, but it’s quite a tough adjustment for me after a month of subfreezing temperatures!)

A final aerial survey just before we left showed
that the lakes were beginning to form ice on the
surface again. As winter returns to the ice, the
lakes will freeze solid and remain frozen
until the next summer. © Chris Linder, WHOI

Our final week on the ice was dedicated to exploring two nearby lakes, one of which had recently drained (dubbed “North Lake”) and another that was partially full of water when we arrived (dubbed “North North Lake”).

North Lake made the news earlier this year when Dr. Sarah Das (Woods Hole Oceanographic Institution) and Dr. Ian Joughin (University of Washington Applied Physics Lab/Polar Science Center) published a pair of papers in the journal Science about the spectacular draining event that they captured with their instrumentation in July 2006. That summer, a giant hole called a moulin opened up in the lake bed and drained the entire water volume (which is a lot; this lake is several kilometers long!) in an hour and a half. This year, the lake was already empty when we arrived (in fact, we had already heard from colleagues that it drained on July 10, the day we arrived at South Lake camp), so the research team had the freedom to explore the empty lake basin on foot.

The dimpled surface on these tilted blocks shows
that these were part of the former lake bed. The
cracking of the ice sheet surface caused them to break
free and float to the surface as the lake drained.
© Chris Linder, WHOI

Our visits to the North Lake basin revealed a bizarre landscape of car-sized blocks, canyons, rivers and waterfalls. The variation in the landscape on the ice sheet, particularly in the drained lake beds, is staggering. I expected it to be, well, flat, and white.

What we saw was quite different—towering blocks of pushed-up ice, rivers of freezing melt water carving their way through 60-foot deep canyons, gaping bottomless cracks and holes. The color of the ice ranges from opaque white to clear to bluebird blue. To my glaciologist companions, the landscape was also an open book. The blocks indicate where major cracks occurred (the blocks are pieces of the ice sheet that are broken loose during the cracking), and the rivers lead us to the crevasses (cracks) or holes (moulins) where the water was still pouring through the ice sheet to the bedrock. If you put your ear to the cracks, you can hear the water echoing in the depths.


Moulins, or holes in the ice sheet,
can be an otherworldly blue.
© Chris Linder, WHOI

It will still be some time before the final picture of the 2008 lake draining can be told. The scientists had only a brief amount of time to examine their instruments and prepare them for another year of data collecting before we had to pack up and fly out. In the coming months, scientists will be examining the data their instruments collected over the previous year. Dr. Mark Behn, a scientist from the Woods Hole Oceanographic Institution’s Geology and Geophysics department (and resident “icequakes” expert), had this comment about the data he did look at:

“Even with a 10 minute look, I can see that the quality of the data is good, which tells me the instruments are working. We can also see the timing of large cracking events that drain the lakes, which stand out as dramatic spikes on the record.”

Be sure to check the Polar Discovery website to read dispatches about our other adventures at North Lake, including the release of a harmless tracer dye into a moulin and the investigation of “North North Lake.” 

Thank you to everyone who came in to the museum on July 21 to talk with moderator Twila Moon and Dr. Ian Joughin live from the ice. Stay tuned for future Live from the Poles expeditions on the Polar Discovery website. Until then, best wishes and thanks again for reading,

Chris

Interested in learning more about Chris, his team and their journey to Greenland?
Learn about the purpose of this trip.
Travel to Greenland with him.
Read what they did their first week.

July 14, 2008: Breaking news from the Greenland Ice Sheet

WHOI glaciologist Sarah Das
hiking on the ice sheet

Greetings from the Greenland ice sheet! A lot has changed since my last post. Instead of shorts and a t-shirt, now I’m wearing double socks (which I thankfully did not forget), thick rubber boots, long underwear, waterproof pants, a long-sleeve fleece, fleece vest, and a waterproof shell. Oh, and don’t forget the hat and gloves and glacier goggles (very dark sunglasses).

It has been quite a journey—a commercial flight from Seattle to Scotia, New York, then a military airlift flight to Kangerlussuaq, Greenland, then an Air Greenland flight to Ilulissat, and finally a 20-minute helicopter flight to our campsite on the flanks of the Greenland ice sheet.

“South Lake” from the air -
it was full when we arrived

A lot has happened since we arrived on Thursday. I can’t possibly describe it all here, so be sure to visit the Polar Discovery website  to see daily photo journals.

The most exciting event happened over the weekend. The science team is here to study the lakes that form on top of the ice sheet, how they drain, and what effect this has on global sea level rise. When we arrived, the researchers were surprised that the lake (roughly 2.5 km in diameter) hadn’t yet drained. There were whitecaps on the lake, and you could hear the sound of waves from our campsite. That all changed yesterday in the space of about 12 hours.

Last night, just after dinner, we heard a BOOM coming from the lake, then another BOOM, and the gushing sound we had been hearing since noon (like a big waterfall) intensified. We immediately began running towards the lake edge. You could feel the cracks opening up below, sounds like rifle shots going off, alternating with booms in the distance like thunder and really creepy swooshing sounds in every direction.

One of the cracks that drained South Lake

After about a half hour, the sound changed. University of Washington glaciologist Ian Joughin swore he could feel the ice rise slightly, and a noise like “snap, crackle, pop” started issuing from the ice.  The research team speculated that the lake water, having finally made it to the bedrock, was shoving the ice upwards. Imagine if you shove a cheesecake upwards from beneath—it’ll crack at the surface, right? Well that’s what happened. There were new cracks forming everywhere; most of them were only a fraction of an inch wide, but running for hundreds of feet into the distance. Meanwhile, the lake level continued to drop steadily. 

After a few minutes of standing in shell-shocked awe (and jumping into the air every time a crack opened nearby), everyone rushed to gear up. This time, we put on hard boots and crampons. The lake bottom ice is very slick, and hasn’t been eroded by the sun like the ice on the sun-weathered ice sheet. 

With GPSs in hand, we scampered off along the lake edge, pointing out new cracks and listening to the steady booms and pops in the distance. Thankfully, the snap, crackle, pop sounds had stopped, and Ian, Sarah, and Mark agreed that it was likely that the slug of water had moved on and was no longer pushing up on the ice sheet. After a few hours of moving slowly around the lake, we found the culprit (to be more accurate, one of the culprits)—a massive crack with no bottom, deep blue in color down the cleft, running right into the lake.  A few small waterfalls were still pouring water into the crack.

At that point it was close to midnight, so we headed home, and are hoping for clear weather so we can investigate the new cracks further.  Everyone is excited—it is likely that no one has ever observed a glacial lake drain like this in person. Not only did we see it happen, but also captured the event with high-precision GPS recorders and seismometers. Be sure to visit HMNS on July 21 to talk to us live from the ice!