Posts Tagged ‘Crane’

h1

Last day on the ice

March 1, 2010

Note from LARISSA team: our sympathies and best wishes to the people of Conception and Santiago, Chile, and the other damaged areas. The Earth can be mighty and implacable, as well as beautiful. Humanity alone knows compassion, and this is our strength

Terry writes:

Our first evening back on the Nathaniel B Palmer was quiet, calm, and starlit. Orion was setting, head down, in a cloudless southern sky. We were in Andvord Bay on the west side of the Antarctic Peninsula, planning the last few possible installations for the cruise. All of them required helicopter flights over the ridge to the Peninsula’s east side. We could only hope that the weather would be clear enough on both sides to allow that, which so far during the cruise had only happened once, and never while our glaciology group was on the ship.

Terry climbed ten feet up the tower to install the replacement camera.

The next morning, Sunday February 21, Ted woke me at 6:15 with the news that we had clear skies around the ship. Erin and Martin’s trip to Foyn Point to install a seismometer was on. Then he said I should get ready to replace the AMIGOS camera at Scar Inlet later that morning as well–even though that was not planned at all. Erin and Martin took off in Barry James’s helicopter around 7:45 while Ronald provided me with some tips on how to test the camera after installation, and how to set up pointing for pictures. But by 8:15 Erin was back on the ship telling us they had turned around due to low clouds on the east side. They were going to try again in an hour or so. This gave me extra time to consolidate the clothing, tools, and climbing equipment I’d need to perform the replacement. They did indeed leave again on Barry’s helo around 10:45, and by 12:30 I had wolfed down a quick lunch, had my replacement camera, my computer, and the rest of my gear loaded onto Chris Dean’s helo. I climbed into the front passenger seat and got strapped in. This would be the third helo flight of my life, but my first one in the forward seat. The feeling up front was somewhere between space capsule and soap bubble.

We lifted off the pad in bright sunshine, the blue waters of the fjord peppered with house-sized icebergs calved from the surrounding glaciers. We flew southeast above Bagshawe Glacier, passing a huge black wall of smooth vertical rock wall laced with an intricate network of snowy cracks. Below us lay a blue-white quilt of ice and snow with a patchwork of seracs (standing ice blocks) and their intervening crevasses. The helo approached the summit of the brilliant Bruce Plateau which at first loomed above us as an insurmountable hurdle (picture), but then flattened into a sloping plane as we came closer. A quick look behind showed an ominous sea of fog approaching our tiny orange ship from the northwest. I feared we’d be racing a closing weather window: the helos had already lost one such race, and the pilot and two explorers had camped on a rocky beach for three days as a result.

We stopped first at Foyn Point to pick up Erin, who would serve as mountaineer at our next stop at Scar Inlet. Just as we landed at Scar Inlet, we received word from the NB Palmer that the fog was only a few miles from the ship. Chris responded that we would leave in about an hour.

We were worried about the crevasse risk, given our experiences on the day we left the AMIGOS site.  Since then the Scar Inlet AMIGOS had been reporting afternoon temperatures as high as 6 degrees Celsius (about 43 degrees Fahrenheit). Warm temperatures can soften and weaken the snow pack covering hidden crevasses, such as the ones we found during the deployment. So immediately upon stepping out of her seat, Erin anchored her rope to the helo skid and then probed with her ice axe outside my door. The top 12 inches or so seemed fairly resistant to probing, so she then instructed me to step out of my seat and to clip into the prussic (a sliding loop of smaller gauge rope) she had rigged for me on her rope. After stumbling for a moment with the prussic, I gingerly stepped into each of her leading footprints until we reached the tower. The whole thing was as close to a space-walk as you can get, I think, on this side of space anyway.

Amazingly, we managed to test the replacement camera, climb ten feet up the tower, and install it, in a little over an hour. The tower moved a bit with both of us hanging on it, but we were chosen to perform this task because we were the lightest-weight team members.

Our return flight went northwesterly, straight back to the ship in Andvord Bay and directly over the outlets of several glaciers that flow east into the Larsen B Embayment. I pulled out a 30 meter resolution Landsat satellite image map from my computer case so I could identify and call out each glacier as we flew over it:  Flask, Stubb, Starbuck, Rachel, Pequod, Melville, Mapple, and Crane. I found it was relatively easy to match up individual ground features seen out my window with the corresponding features from the image map: a distinctive line of peaks here, a tributary glacier flowing in there, etc. The weather was still very clear where we were, although I did notice some fog obscuring the sides of Crane Glacier where I was hoping to see the “trim line” that marks the previous level of ice before the dramatic drawdown of the glacier that has occurred since 2002. I was so busy looking for the trim line on Crane that I completely missed noticing the calving front that was clearly visible from the our left side seats as revealed by Erin’s photos. Oh well, maybe next time.

Later that evening Ronald and I were able to confirm that images from the Scar Inlet AMIGOS were indeed being received and that the camera seemed to be working perfectly. And although we needed to adjust the camera positions (which we can do remotely), it turns out that just by chance one of the views appears to be looking directly up Flask Glacier, which is one that we’ll probably keep.

We did it. We used every resource in the program to do it, but we did it: three AMIGOS, and two GPS, sitting on some of the most dynamic, vulnerable ice on Earth.  Now we’re sailing north towards Punta Arenas, packed up, and wondering what’s next.

Advertisements
%d bloggers like this: