This map, published by McMurdo's field safety team (FSTP), shows current sea ice condtions in the southeastern portion of McMurdo Sound. You can see the red crack extending from the glacier tongue that, at the time the map was made, was presumed to extend not too far to the west.
For the last couple of weeks we’ve been battling worsening sea ice conditions in McMurdo Sound. Cracks between the different pans of land fast ice keep growing wider, and though they freeze quickly it can take weeks for the ice to be thick enough to travel over by McMurdo Station rules. One particularly troublesome crack extends west from the Erebus Glacier Tongue effectively blocking all travel north of the tongue. All throughout September we were able to travel over the crack safely, but it has widened significantly over the last two weeks. Since our Tent Island sampling site is on the other side of the crack this presents a bit of a problem for us.
Today Shelly and I went out with Jen and another field safety staff member named Susan. We thought that be traveling far out to the west, toward the center of McMurdo Sound, we’d be able to do an end-run around the crack. We put a lot of miles on the snowmobiles heading west without the crack showing any sign of tapering off! Unable to run around the end we measured the thickness of new ice over the crack in a few spots to try and find a safe crossing. This was tough work. It’s a wide crack and the irregular edges of the ice here had collected large rock-hard snowdrifts that had to be dug down to the ice surface. When snow drifts and solidifies over a hollow space (like a crevasse or open water) it’s called a snow bridge. Snow bridges and can be remarkably strong. We had no doubt that the snow bridges and ice underneath would have supported our equipment and more, but the science teams have been issued strict instructions not to deviate from station rules. Oh well!
Attempting an end run, but no end in sight!
As a consolation prize we were visited by a group of Emperor penguins at the farthest point west that we reached. In contrast to the group that we saw a week ago, which was hunkered down for a storm, this group was quite active. They spotted us from a ways away and, being naturally curious, came right on over. We took a mandatory penguin-watching break and sat down to see what they would do. It was a funny exchange; they got remarkably close to us and then stood and stared (while we stared back). After about 45 minutes, cold and mindful of the fact that we still had a lot of work left to do, we finally get up and started getting ready to go. Satisfied, all but one of the penguins wandered off to find more interesting things on the ice. The remaining bird followed us over to our snowmobiles and kept staring even after we started them. I think he (she?) would have taken a ride had it been offered.
Curious penguins coming to check us out.
Tomorrow Shelly and I will head back out to try and get some ice cores. Since we can’t get to Tent Island we will have to try and find a site on this side of the crack that mimics our old site as close as possible. That’s far less than ideal, any number of differences might exist between ice collected at the two sites, but that’s how field work goes sometimes! It often seems that it goes that way most of the time…
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