9 December, 2000

Weather

Weather is a big part of the Antarctic experience. It can be severe and it often changes suddenly. Many of the activities that go on here depend upon weather.

After being at Siple Dome for two and a half weeks, it is clear that the weather is different here than at McMurdo Station. Siple Dome is higher in elevation (622m or 2040ft) and far from the Ross Sea (400km or 250mi). This makes the climate both colder and drier. McMurdo just had one of its snowiest Novembers on record with over 60cm (24in) of snowfall. We have had only about 2 centimeters of snow since I arrived.

There are three elements of weather that have an effect on life at Siple Dome. The least important seems to be air temperature. The high temperature usually occurs around noon and averages about -7C (19F). The low usually falls around midnight at an average of -15C (5F). That sounds cold but I think people get used to the low temperature and don't really notice the differences.

The sun itself is an important element of the weather. Of course it is always up. When it is cloudy, it feels colder, and the visibility is often poor. When the sun is out, the whole atmosphere of camp changes. It seems warmer, you can see to the horizon, and it is beautiful. The field camp at Siple Dome uses the same time as McMurdo Station and New Zealand. Because we are farther east at 149 degrees west longitude, solar time is quite a bit earlier. Solar noon, when the sun is highest in the sky, occurs at 10:39 am. The sun gets to about 30 degrees above the horizon this time of year. The sun is lowest, about 10 degrees above the horizon, at 10:39 pm.

The most influential element of weather here is the wind. When it blows, the cold seems to go right through your clothing and any exposed skin can get painfully chilly. If the wind blows hard, it picks up surface snow, which can reduce visibility to a few meters.

Today happens to be one of the nicest days we have had. The temperature is -5C (23F), the sky is clear, and there is no wind. It seems very warm. I'll have to open the tent door tonight so it doesn't get too hot.

During this storm the winds reached a speed of 12 meters per second (27mph). A couple minutes later the blowing snow completely obscured the Jamesways. Just for fun I bundled up, put on my skis and went out to the runway. The wind blew me all the way to the other end without any effort on my part.