Sunday, November 22, 2009

The Ice Edge

The Ice Edge. The ice edge is cracking. The ice edge is coming closer. The ice edge will be here by the end of the month. The ice runway is closing because the ice is so weak. The ice is going to make it all the way to town this year. Cape Evans trips are going to end early because the ice is blowing out so quickly this year. The ice edge might make it town. The ice edge is coming, the ice edge is coming. These are the whispers I am hearing through town on a regular basis.

The ice edge as of November 4, 2009.

The ice edge as of my birthday, November 26, 2009.
Click either picture for a better view. McMurdo is the red dot. The Dry Valleys are the brown areas to the left of the red dots.

What is the big deal about the ice edge coming closer? In March 2000, a very, very large piece of the Ross Ice Shelf broke off to form what would become known as the iceberg B-15. At 295km long and 37km wide, the iceberg encompassed an area twice the size of Delaware or three times the state of Rhode Island. Helicopters would land on it. It even affected weather patterns. This iceberg blocked McMurdo Sound and the Ross Sea for a few years so that the annual ice floe could not break up and blow out to sea. Each year that the ice didn't blow out, it got thicker, heavier, and harder to blow out the following year. While B-15 broke up and blew away a few years ago, it has had lasting effects.

When the ice floe didn't blow out, it meant that the penguins in the colonies nearby had a much longer 'march' from their nests to get food. The extra effort needed to get food for their chicks led to decreased survival rates. It also, and more importantly, meant that the ice edge never reached town. The penguins spend time near the ice edge so that means if the ice edge was close, the penguins would be close where we have a much better chance of seeing them. Lots of old timers talk about the way penguins used to come right to town and bring all their friends with them. I can only hope that will happen this year.

The current sea ice edge about 15 miles from town and why I want it to come closer, PENGUINS!

Some of you might remember that ships come to station every year and wonder how that happens with all the ice in the way? This location was originally selected by Scott because it is, or was, the southern most navigable ice free port in the world. It allowed his expeditions to move goods with minimal effort. The ships that have come down here have always been icebreakers or escorted by them. Larger ice floes just meant more ice breaking. Unfortunately, the ice edge they create is really a small channel and doesn't bring the penguins in the same numbers as if the actual ice edge comes in.

One of the other cool things about the chance to see a lot of open water is that this place seems to come alive. For most of the year, the surface around us doesn't change. Things don't grow. Colors don't change except snow white to volcanic black. When we get water, we get a new color and the constant movement of that water. Some people will just stare at it when they see it. I can't wait!

Edit: This weekend is the final weekend for trips out to Cape Evans because the sea ice is deteriorating. They should be closing the ice runway next week as well.