A New Home on the Ice

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. Today – in addition to sending us weekly updates -Chris and fellow researcher Dr. Ian Joughin made a live call to our summer campers in the Burke Baker Planetarium; we hope to post the audio from the call here soon. If you’ve got questions of your own, visit us tonight – they’ll be calling us back. For now, here’s more from Chris, from the ice sheet: 

The camp at North Lake

We have been camping on the ice sheet for over a week now, and it’s amazing to think how familiar this environment now seems, especially compared to how foreign it felt when I stepped off the helicopter.

Some of the peculiarities of living on a 3,000-foot thick slab of ice:

- Water: you don’t have to carry a water bottle on a hike, just a cup. The water is the best tasting I’ve ever had.
- Cooking: no refrigeration required! We made a no-bake cheesecake the other night and it was quite a treat. Just left it outside the cook tent to chill…
- Slippery tents: instead of using tent stakes to secure the tents, we use ice screws, which are 6-inch metal screws. The problem is, they heat up in the sun and melt out after a day, so we spend a lot of time repositioning the ice screws.
- No night: this is a tough one—the 24 hours of daylight make it hard to sleep and it’s easy to forget what time it is.

The past week has been a busy one—we typically wake up at 8 a.m. and sometimes don’t finish work until 1-2 a.m. The science team has been working nonstop to refurbish their long-term instruments and survey the terrain by foot and air. They successfully installed two new instrument towers on the shores of the recently drained South Lake, which will measure the weather, icequakes (using a seismometer), and the movement of the ice sheet (using a sensitive GPS). For more information about the tools our science team uses to track moving ice, visit the Polar Discovery tools page

View of a glacial lake from a helicopter

We also completed an hour-long helicopter survey of 20 nearby lakes. An aerial perspective gives you so much information that you can’t get from either the ground or from a satellite.  You can see immediately the water level in a lake, count the number of inflow channels, and see where the lake is draining (if at all).  The weather cleared during the survey and we had magnificent views of the glacial lakes – full ones, empty ones, and draining ones.

On July 16, we disassembled our carefully constructed home at South Lake and packed everything up for a move to North Lake.  Although much of the work will be similar to what we did at South Lake (removing existing instruments, assembling new ones, and field mapping by foot and helicopter), the research team is expecting to see different processes at work here. 

Last year, South Lake drained through a huge downstream channel, while North Lake gushed through a gaping hole called a moulin right in the center of the lake.  This year, new observations at South Lake confirmed that the water primarily drained through a huge crack that ran right through the lake. 

In the coming days, the science team is hoping to piece together this year’s story about North Lake, how it is similar and different from South Lake, how this knowledge can help to understand the thousands of glacial lakes that form on the ice sheet each summer, and what conclusions can be passed along to researchers modeling the global climate. Don’t forget to visit Polar Discovery to see daily photo essays!

Newly installed instrument towers at South Lake

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!