11 January 2015 WAIS Divide 101: Part 2

All about the WAIS (not the treble)!

What is an Ice Sheet?

You may know that Antarctica is the highest, the driest, and the coldest continent on earth.

It's considered the highest, because there are, on average, 2 miles of snow and ice piled on top of the continental land mass.

However, what people often don't realize about Antarctica is that it is a desert. The continent, on average, receives less than 10 cm of rain or snowfall per year. While some places (like WAIS Divide) receive more, some receive even less.

In the Dry Valleys, for example, it has not rained or snowed in over 2 million years!

You are probably wondering how this is possible.

If it only snows 10cm a year, how can there be 2 miles of ice piled on top of this continent??

Well, the answer to that lies in the fact that this is also the coldest place on earth.

Although it does not snow very much each year, the little bit of snowfall does not melt away at the end of the winter. Instead, each year, a fresh batch of snow falls, gets piled on top of last year's snow, which is piled on top snow from the year before that... and so on.

As more and more snow falls each year, it presses down on and compacts snow from the years before it. That snow turns to ice, and, as more gets added, it eventually forms an ice sheet. The ice farthest toward the bottom is the oldest ice, and the snow on top is the newest.

At WAIS Divide, we are on top of more than 2 miles of snow and ice. At the bottom of this ice sheet is the snow that fell 68,000 years ago!

To be continued...