5 November, 1999
It snowed today. (See picture below) This may not sound like a big deal but considering that this is the driest of all continents, the snow today surprised me. It was moderately heavy snow with large flakes. In fact, I have already seen more snow since I have been here than I expected to see. Maybe Antarctica isn't as dry as I thought. I decided to compare the precipitation in McMurdo to my hometown, Appleton, Wisconsin. If you compare the snowfall charts for McMurdo and Appleton, in the upper Midwest of the United States, Appleton gets less snow over the course of the year (Although Appleton has snowier months in the winter). However, in terms on total water equivalent (i.e. the amount of water that falls in the form of snow, ice or rain) it is much different. Appleton gets about 31 inches of precipitation each year and McMurdo only gets 7.5 inches of precipitation a year. Remember, McMurdo get virtually all of its precipitation in the form of snow. The average total water equivalent for the continent is less then 5 inches. Most of the precipitation that does fall is on the continental margins. The average water equivalent of precipitation on the polar plateau is less than 2 inches! So, yes Antarctic is very dry.
The reason there is so little precipitation is that the air in Antarctica is very dry. The Antarctic atmosphere, because of its low temperature, contains only about one-tenth the water vapor concentration found in temperate latitudes. What moisture that does enter the atmosphere largely comes from ice-free regions of the southern oceans and is transported in the troposphere into Antarctica. The snow we had today was due to a storm bringing moisture off the open water ot the seas near McMurdo. Snowstorms are not the most feared storms in Antarctica. That honor is reserved for the "herbie" Herbies are the most powerful and dangerous storms on this part of Ross Island. They come out of the South bringing winds that can be in excess of 100 knots These winds can cause blowing snow that makes visibility go to zero and wind-chills to dangerous and even life-threatening levels. A herbie can hit an area very quickly and trap unaware Antarctic travelers. A moderate herbie hit Mactown today. It has caused Condition One and Condition Two levels in this area. Travel is restricted. No flights came in or out of McMurdo today. As I sit now in Crary Lab typing this journal, I can hear the wind howling and outside the window I can only see about 100 yards. It will be a very interesting walk back to the dorm.
Special Note: I will be starting an evaporation experiment on Monday. For those of you from schools I have visited, you should have a copy of the experiment in your packet. It's called "Going, Going, Gone!". I will set up the experiment on Monday morning (Central Time in the US) and I will post my initial data and keep you posted on results. You can compare my results with yours. If you would like a copy of the experiment, e-mail me. I will send you a Microsoft Word file with the experiment. Remember that I will start it Monday.
Featured CRP Team Members: These are the paleomagnetists (or as they are sometimes called, paleo-magicians). They determine the strength and orientation of the magnetism in the minerals in the core samples. From this information they can help determine the age of the rock and the environment which they were deposited. The CRP team members pictured below are Fabio Florindo from Rome, Italy, Adam Harris from Davis, California and Gary Wilson from Oxford, England.
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