Brian Powell

8/14/05: Well, I hadn't updated in a couple of days as we were busy with our ice camp. When I last wrote, we were going to continue CTD casts to the west of the rise; however, on Friday we ran into a floe which seemed perfect. We set up all of our equipment both Friday and Saturday. Everything was working well all day Sunday. In fact, Peter Guest and I had time to go out and fly a kite with a radiosonde attached to it to take profile measurements over a number of areas. It was a beautiful day for kite flying: temps were only about -16C, no clouds, just enough wind to provide the forces required for successful kiting. We came in about 4pm. By 6pm, I was in the sauna, and at 8pm, the emergency ensued. A large crack had formed and split the ice creating a sizable leed which was heading for all of the equipment. A number of us donned our suits and rushed out to take down all of the instruments (or pull up depending on what they were measuring) and get everything back to the ship before the ice separated. What took nearly 2 days to assemble was dismantled in a mere 90 minutes and lifted back onto the ship. A number of hairline cracks (where the snow separates but the ice does not separate) formed around us while we worked (we weren't in danger, it would take 1-2 days of strong wind to separate the floe at those cracks) which was fascinating to look at up close. After 3 days of a winter wonderland atmosphere, we have to spend a night of quiet reflection and make decisions tomorrow about where to continue. It wasn't necessarily unexpected. Typically in this area, the mixed layer (the upper portion of the ocean that is homogeneous) is about 120-150m deep. On this ice floe, the measurements we took over the last 3 days showed a mixed layer of roughly 12-20m. This means that very warm water was being brought to the surface from below. As soon as a strong mixing event (wind) occurs, the mixed layer will be formed again, but equalizing with this warm water, which will melt the ice from the bottom. So, the moral is that we realized the floe was not going to last, but we were hoping for another 3-4 days rather than the 3 hours we got after discussing it. Well, it no longer exists, but I have included a picture of one of the huts in the ice camp for your enjoyment (for scale, the hut is about 8 ft tall and the ship is about 400m away)...

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