Nearly three weeks at McMurdo gave us a good chill about weather in Antarctica and its predictability. The last days partly felt like never ending SIO coffee hours with all the project Scripps partitioned that this season (see San Diego Union Tribune).
Today is the day of take off to camp: They day when we say good by to frosty boy, heated buildings, US TV and a lot of comfort you really wouldn’t expect down here. We will exchange the spectacular view on on the trans-antarctic mountains with a 360 deg view of nothing else than a horizontal line. Our days will be filled with searching for solar panels and then digging holes in the snow. Not beautiful, but fast. We will leave nothing behind the nature itself, but will know the shelf’s movement, measured continuous and accurate as never before.
We are done, when we are done. See you in about 3 to 5 weeks!
Our training is starting to get more serious. In addition to packing smaller boxes in big boxes or even unboxing boxes for the cargo stream, we also spend our preparatory time here at McMurdo in field training courses for all kinds of hazards we may face. One of the more enjoyable trainings so far has been the Crevasse Training, which prepared us for one of the most critical dangers traveling on ice shelves. Even though it is very unlikely that we’d encounter crevasses in the areas of the Ross Ice Shelf we’ll be visiting (there haven’t been any within the last 2 years), it’s essential that we’re prepared for any situation.
Crevasses are ridges in the ice that occur due to bending forces. They can be anywhere from a few feet to several tens of meters deep. Since the Ross Ice Shelf is about 400 meters thick, very long and deep crevasses can easily occur. Winds can blow them full with snow or produce overhangs, making them difficult to spot when traveling on the shelf.
The occurrence of crevasses is poorly understood and, in fact, one aim of this project is to gain a better understanding of their occurrence in floating planer ice shelves. The shelf floats on the ocean and has to adjust to changes of the sea surface height following the principle of Archimedes. Further, the thicker the ice the more inertia you need to induce measurable motion. Since the Ross Ice Shelf is grounded to the Antarctic continent in the South, the buoyancy force from sea surface height variations (due to storms, tides, and other processes) induces stress leading to bending in the ice. Just like bending a piece of wood, if you keep bending for long enough and with sufficient force, cracks will begin to form. In an ice shelf, the permanent small bending forces from ocean tides and waves may be enough to produce ridges that propagate and extend in time.
The first (and indoor) part of the crevasse training included climbing up a short section of rope (with Prusik hitches) that was being constantly lowered, as Sisyphus would have had experienced it. We also learned how to use mechanical advantage to establish 3:1 and 6:1 (two people) pulleys to drag grad students along the floor. Tying knots and organizing rope inside a heated building is one thing, but doing it outside on day two of our training in full extreme cold weather (ECW) gear was another story. We headed outside to the McMurdo Ice Shelf just beyond Scott Base on Tuesday to practice anchor building and crevasse rescues in a ~25ft “simulated” crevasse created by our USAP mountaineer guides. Although the day of practice outside was good fun, we hope we’ll never be required to use the crevasse rescue skills we’ve learned. Stay tuned for our next post!
Being in Antarctica is an exclusive experience and we can barely imagine how the first discoverers felt in their early expeditions. Many of these early voyages to Antarctica, around the turn of the 20th century, found a safe harbor in the McMurdo Sound, landing on Ross Island where McMurdo station stands today. One of the few remnants of early Antarctic exploration near McMurdo is “Scott’s Hut,” which we fortunate to visit during its brief opening to the McMurdo community for several hours last Sunday. A few minutes by foot along the coast beyond McMurdo station, this wooden hut stands well preserved from the days when it was used by the British Captain Robert Scott and his men. Many artifacts inside the hut remain intact, ranging from a box of dog biscuits to a dried out seal body! During its periodic public openings, Scott’s Hut is popular among the McMurdo population, who trek out in “Big Red” to have a look inside this historical place.
Upon entering the hut, we were informed that anything that might be moved, scratched or even viewed from the wrong angle would be recorded and reported to the New Zealand Antarctic Heritage Trust with the potential for further consequences. With this in mind, have a look at our pictures of Scott’s Hut which we visited in today’s physical Antarctic climate – much like Scott’s – and today’s bureaucratic climate, put in place to conserve this important historical site.