Halleys

Life around this area has never been easy and all the comfort and safety that we have around here today is something quite recent in the lifetime of this base. The name of the station has a “VI” for a reason. As I referred before, this is the sixth attempt to create a permanent habitation around these parts.

Before explaining what happened to the other five, there are two particular phenomenons that only happen here and transforms the construction of any kind of habitation, either a house, a small control booth or an open air latrine, a considerable challenge.

First point to consider: we are in an ice shelf. About 130 meters down into the centre of the planet we have… salt water, or better, the Antarctic Glacial Ocean. This shelf is basically formed by a collection of icebergs, united among themselves by frozen ocean water that gets trapped in the middle and some snow.

In a very simplistic way, the formation process of these shelfs starts by big blocks of ice that fell from the continent into the surrounding ocean – icebergs. At those latitudes they don’t float for long. It’s so cold that the surface of the ocean between icebergs freezes eventually, gluing them together. Also it is important to point out that around the edge of the continent it rarely rains. Most precipitation is in the form of snow that, in turn, fills the gaps between these icebergs, with the frozen ocean surface forming the bottom of the jar. After a couple of years, while these packed icebergs are pushed away from the continent by others that are falling from it in the meantime, the ice shelf gets this pretty and smooth snowy look that appears in my photos.

What is the problem then if we decide to build a nice vacation house in the Brunt ice shelf?

Two big problems actually: first, as I mentioned before, the shelf is constantly moving towards the ocean. Doesn’t really matter where we put our house initially. Eventually we will gain an ocean view from the kitchen window and a few years later our little house is gonna be on top of an iceberg, calmly floating North. Yep, the shelf doesn’t stop growing and there always going to be a point where part of it will split into the famous icebergs that I’ve photographed on my way here.

The second problem consists in snow accumulation. Unlike in most of the civilized world, where it snows in the Winter but then it melts in Spring and Summer, around here, even in the peak of Summer, its rare to get temperatures above 0º. Last Summer, the maximum that we got were a tropical +0.5 ºC, during a particularly “hot” day in January. What happens then to the snow that fall throughout the whole here? Nothing and that’s the problem! It will simply gets the shelf thicker and thicker. Than whats the real issue after all? With over a meter of snow deposition per year, five years are more than enough to bury most building up to the top. Simple. Its something that we have always to account for. It took years and some technological improvements to understand exactly how the dynamics of this ice shelf operate. Halley VI is the result of that knowledge applied to engineering. Now that you know what to expect from this place, it  isn’t hard to guess what happened to the other five bases:

HALLEY I (1956-1968): The very first attempt of building something around these parts consisted in a “simple” wooden shack. Actually there were to houses build during this period, the second one to compensate the progressive burying of the first one. In the last years of usage of these habitations, entrance was done through the roof since the main door had been buried a long time before.

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HALLEY II (1967-1973): The second attempt was not that different from the first. Wood was still used for the outside of the building but now with some metallic beams as roof support, as a way to hold off the pressure from the accumulating snow and extend the building usage for a couple more years.

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HALLEY III (1973-1984): This time, prefabricated two story houses were used with plates of corrugated steel on the sides to counter balance the pressure of the snow and ice has the buildings were getting swallowed by the shelf. Using taller buildings increased their usage period since it took more time for them to get completely buried.

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HALLEY IV (1983-1992): This was the first station projected to be buried on purpose. It was basically a series of plywood tubes, also protected by sheets of corrugated steel on the outside. The entrance was done by another vertical tube connecting to the outside and with the objective of increasing this entrance tube each year to compensate snow accumulation whilst keeping the station operational a few meters below the surface. Truth is, it was a sound idea until a point. The temperature inside the shelf ice varies only between -15º and -19ºC, while during the harsh Winter months, air temperature can reach easily -45ºC or even lower. Yet, as the stations was progressing into the bowels off the shelf, the pressure along the wall was increasing and, worse of all, it wasn’t uniform. This pressure imbalance forced these tubes to twist and bend, which made life inside this station very frightening and dangerous. I’ve met a couple of people that worked in that station and they told me how scary it was to be inside a hole where all the support beams were bent and cracked and you listen to a constant background noise of wood breaking.

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A few years after this station was abandoned, it surfaced again in the edge of the shelf. It was so deeply buried that it wasn’t decommissioned properly and the movement of the shelf towards the sea eventually showed its remains, before becoming part of another iceberg.

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HALLEY V (1992-2012): This was the first station build with the purpose of staying above the snow level instead of trying to survive while getting buried by it, something that the previous stations had proven to be impossible. The concept is so simple that even today is still used in many of the auxiliary structures that we have around here: the body of the structure stays suspended on metallic legs a few meters above the shelf surface. And these can be extended any time by adding new sections to the top while the body can be hoisted along these legs. Halley V was more similar to an ocean oil platform than anything else but the concept proved to be sufficient to keep the station running for 20 years, a record until that point.

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Every year, during Summer, part of the season was dedicated to hoist the main building along the metallic legs to compensate the surface rise due to snow accumulation. It seems perfect right? What was then the problem that forced this one to be abandoned too? Well, the base avoid the yearly burying that’s for sure, but it was fixed to the same point in the ice shelf. And this point, as mentioned before, was moving towards the sea surprisingly fast. Halley V was abandoned and decommissioned since it was getting to close to the zone were icebergs are born.

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HALLEY VI (2012-Present): Taking the previous concept a level higher, Halley VI is also prepared to avoid unwanted ocean dips. Starting from the anterior plan, that is, the station’s body suspended over the ice shelf surface, a new innovation was added: instead of steel legs deeply buried into the ice we now have… gigantic skis! And with another advantage: the station’s legs are now hydraulic. Every Summer, as already happened with version 5.0, in a initial phase, all legs are unburied from all the snow accumulated during last Winter and flexed on top on the higher surface. With all of them lined up and with the station horizontal, the next phase consists in stretching the legs which elevates the station as much as possible. After this its possible to put the station in the same state as it was a year before without using any metal or other weird contraptions.

As with everything around here, this station also gets near the ocean with every passing year, but with this one is now possible to tow it back away from the sure whenever its necessary.

Since its not a small nor light station, the terrain adjustment is only made if it gets to close to the shore, since its impossible to move it as a whole. Its necessary to split all the modules and move them, one by one to their new positions, and reattach the whole thing back together and that is something that you don’t do in a single afternoon.

In theory, this is a station that should last forever.

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