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Weather and Sea Ice

Sunday, 10 September 2000



    It is amazing how quickly the days change. When I arrived here a little over a week ago, it was dark when I began work in the morning. Actually, the sky did not begin to lighten until around 8:00 A.M. and the sunrise wasn't until after 10:00 A.M. The sun would set a little before 4:00 P.M. and the sky was dark before I finished work in the afternoon. Barely a week later there is light in the sky when I wake up in the morning and I can watch the sunset after I finish work at 5:30. It will not be too long before I will be sleeping through both sunrise and sunset, and by the third week in October the sun will stop going down altogether.

    McMurdo Station sits in a little valley right on the coast. It is a somewhat protected position, although we do sit in the shadow of Mount Erebus, the world's southernmost active volcano.

McMurdo Station viewed from the sea ice

When the sun comes up in the mornings it rises behind Mt. Erebus, and there is the most gentle light hitting the mountain range across the bay. It is very subtle and difficult to photograph, but quite lovely. The Royal Society Mountains (a portion of the Transantarctic mountain range) are bathed in pink. The sound between us is not yet lit, so is a lovely shade of blue.

Royal Society Mountains at sunrise

In the evenings the sun sets behind the Royal Society Mountains putting them in silhouette against a red sky. Because the sun is traveling at such a low angle, the sunsets last for hours.

Sunset over McMurdo Station & McMurdo Sound
Sunset behind the Royal Society Mountains
Mt. Erebus bathed in sunset

    There is a phenomenon down here called nacreous clouds. I do not know if this is something which is indigenous to Antarctica, or to very cold climates in general. I suspect it is as it has to do with ice crystals in the sky and some cirrus cloud formations. The clouds look like mother of pearl with many colors and lovely patterns. I saw a few of these last season and was very impressed, but what I saw then cannot begin to compare with what I have seen this year. I am guessing that it's because I am here earlier in the season when the sun drops below the horizon and the temperatures are colder. The sky is reminiscent of a science fiction movie, but I am seeing it with my own eyes. Of course the photos don't begin to do it justice. It is truly breathtaking.

Nacreous clouds
Nacreous clouds
Nacreous clouds
Nacreous clouds

    Last season when I was here we began doing renovations on building 155, the main building in town which houses the galley, the store, the barber shop, the ATM machine, the television and radio stations, the library, etc. Down here whenever people complain about things being hard or difficult the standard reply is, "Antarctica — it's a harsh continent." It is a phrase you hear frequently in response to many things. When there are no fresh vegetables for several months, or when you have to work outside in severe weather conditions, or even when you can't get the computer to work right, someone will invariably say, "It's a harsh continent." One of the projects the winter crew had to do was to renovate our galley. They did a beautiful job. We have all been joking about how McMurdo is turning into a regular "Club Med" these days. Some things have really become quite comfortable. Even the Coffee House is serving "smoothies" (from a frozen base of course). Now when someone complains that the sauna is not hot enough, you hear, "It's a harsh continent!"

Galley renovation
Galley renovation
Galley renovation

    In the big picture, however, Antarctica still is a harsh continent. Storms can come up without warning. It is amazing how quickly the weather can change. Last season, I saw a few storms, but nothing like what I have heard stories about. I decided to come down earlier this year in the hopes of experiencing just one of those storms. So far this year the weather has been pretty mild, although at times rather cold. I have worked outside several days this week, including one day when the wind–chill dropped down to –67°F. Surprisingly, when properly dressed, I was not too uncomfortable. On Friday we had a small storm with winds of 33 knots which blew a lot of snow into town.

    There are still many dangers and we are constantly being warned or trained for one thing or another. On Friday I had to attend Sea Ice training. People began studying the behavior of sea ice in the 1950's after Willy Williams, for whom our Williams Field is named, died when a crack formed in the sea ice and the tractor he was driving fell through. Since that time they have learned much about how sea ice behaves and no one else has died. There have been a few accidents, but not too many, and all have survived. Anyone who has to spend time out on the sea ice must go through training. We learn about where and why cracks form in the ice, what shapes they will make and how to identify them. We spent half a day in the classroom and then got into a Hagglund, a tracked vehicle which is also amphibious, and went out on the ice to look for and test various cracks.

Sea ice class and Hagglund

    If you think that driving over the sea ice is a smooth drive, think again. It is a terribly bumpy ride. Several of us have large bruises from being banged around inside the Hagglund. There are windows, but they get terribly frosted up. You can scrape them, but the ice is hard and it is difficult to get off the glass. It may take a good 10 minutes to scrape down, and then will freeze again in under 60 seconds. The front cabin of the Hagglund has some heat. The back section has no heat, and although you are out of the wind, it is still uncomfortably cold. When we find a crack we stop and drill in various areas to test the thickness of the ice. Unfortunately the weather was very overcast, so the photos are not very clear. Shooting white snow on an overcast day does not offer much contrast.

Crack in the sea ice
Crack in the sea ice

    If a crack is less that 30 inches deep for more than 3 feet, then we are forbidden to drive across it even in a tracked vehicle. We found several cracks which were only 12 inches deep, but not very wide, and the ice on either side of it quickly grew to thicknesses from 4 to 12 feet.

Drilling the sea ice to test the thickness
Drilling the sea ice to test the thickness

    If you see seals on the sea ice, you can be sure that a crack is nearby. The seals have to chew holes in the ice so that they can come up to breathe and to get on top of the ice. Chewing through 6 to 10 feet of ice is quite a job, so they will look for the thinnest ice to chew through. That, of course, would be where the cracks are. Sure enough we found a few seals lying on the ice and went over to investigate. They were not too concerned with our presence. They looked at us, but did not bother to move. They are quite adorable.

Weddell seals

    As the weather can change without warning we never leave town without survival bags. Each bag contains a tent, a sleeping bag, a shovel, ice pick, food for 3 days, a small gas stove and several other things. It is pretty bare necessities, but designed to keep you alive in a severe emergency. Our last order of business for the day was to learn how to pitch and secure a tent on the sea ice. As we were pitching our tents the weather did take a turn for the worse. The wind picked up and things got very uncomfortably cold. Our fingers were all aching before those tents were finished. But we got them up. We had to use the G.P.S. system to get us back to town as the visibility out on the ice had gotten so poor. All in all, it was an interesting day. I hope I never need to use those emergency skills, but I am awfully glad to have had the opportunity.

Erecting a tent on the sea ice
Our sea ice training class

There should be some exciting things coming up which will make use of our sea ice training, but I will save that for future stories.



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Irma Hale
McMurdo Station, Antarctica
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