Sunday, March 25, 2007

A Few Days Off Base & Some Local Geography

Having intended to write an entry every fortnight, I can feel the resolution slipping from my grasp already. The highlight since last writing has been the pre-Winter trip. Everybody has the opportunity to spend a week away this side of the winter and a longer period of time once the sun reappears.

Second Chasm, The Hinge Zone
In the foreground are laden Nansen sledges, in the distance the Antarctic plateau

Ostensibly the trips are part of a modular field training course, led by the Field GA (General Assistant- though the title is misleading in that they are without exception highly skilled mountaineers), so that we could undertake fieldwork or in my case Search and Rescue (SAR) operations competently. The other role of the trip is the chance for everybody to get off base and spend some time out in the middle of nowhere. We are fortunate however, since apart from possibly one other National Antarctic program, BAS is the only organisation which undertakes such trips during the winter.

Sledge Charlie Prepping in the Laws Corridor
From L to R Sune, Chris, Brian

The intention is that everybody spends six nights away before the winter and then have a second longer trip after sun-up. Traditionally the first trip is to the Hinge Zone, which lies about 30 miles south of the base. Halley lies on the Brunt Ice Shelf, a large sheet of ice 250 metres thick that sits on about 150 metres of water. The continent itself starts the other side of the Hinge Zone, where the Antarctic Plateau rises out of the sea underneath the ice sheet. The major dynamic force near the Shelf is the Stancomb-Wills Glacier, a huge ice stream named by Shackleton after one of the major sponsors of his 1915 expedition and shares its name with one of the lifeboats in which he crossed the Southern Ocean to South Georgia. It lies a distance west of Halley and runs in a northerly directions off the continent into the sea, however it creates a pressure of ice that generates a slow westerly flow of ice across the Brunt.

The Brunt Ice Shelf
The large Stancomb-Wills Glacier lies to the west of the map

Though the Brunt is effectively floating free upon a layer of sea-water, it is grounded in one place, the McDonald Ice Rumples, where an undersea rocky promontory, though only a couple of miles across in either direction rises up to stabilise the shelf; these are traditionally the venue for the second trip. Given the continual flow of ice there is a constant loss of ice into the Weddell sea, forming a front towards which the base moves between half- and a full mile a year (which explains the varying GPS positions of Halley V).

Abseiling Off Stony Berg
Chris (L) prepares to descend under Sune's (R) supervision

Though several of the previous bases were abandoned due to their increasing proximity to the sea, there is an expectation that despite the stability provided by the Rumples, the Brunt will calve at some point in the near future. Calving involves a large part of the shelf breaking off and was last thought to have happened in around 1949. It is predicted to happen again in the near future though nobody is able to predict when, when it does go, however, it is likely that it will take the current base with it, hence the need to build a new station, Halley VI, which will start life about 10 miles east and slightly south from here.

Sledge Charlie Camp Site in Second Chasm

The Hinge Zone meanwhile is a large area where the shelf slopes down and attaches to the continent and from where the plateau gradually rises up, an area known as the Caird Coast, again named after one of Shackleton's patrons. The area is heavily crevassed and undulating but is dominated by several large depressions, First, Second and Baby Chasm; it was in the second of these that we camped for the duration of the trip. Each Sledge party takes a call sign for the twice daily radio contact, taking the moniker Sledge Charlie, a distinct lack of imagination on our part meant that we (myself, Sune- Field GA, Brian- Plumber and Chris- SHARE Electrical Engineer), failed to corrupt it to anything more exciting.

Ski-doo Travel Roped Up
Sastrugi cover the ice surface catching the link rope

Undertaking a field trip, particularly a winter one, is not a lightweight expedition. The whole set-up revolves around travelling in pairs, an extension of travelling roped-up in Alpine pairs as when on foot in any crevassed area. When travelling on ski-doo the lead 'doo is connected by a short rope to the first sledge, which then has a longer link rope running to the front of the following 'doo. A third rope runs to the final sledge, so a linked pair extends over at least 30 metres; each driver is then attached separately by rope to their own 'doo. The idea is that should any part of the chain fall into un-anticipated crevasse, the sledges would brace the fall and the driver would still be roped in.

Linked Ski-dooing Across 'The Superbowl'

Within each pair only one sledge is really needed, while the second sledge along with a large proportion of the first, carries spares and emergency kit; each field party could quite comfortably live in the field for six weeks longer than intended, even then on full rations. The sledges themselves have a long heritage, as they are still built to the design of Nansen, the father of Polar sledge exploration who adapted a traditional Norwegian design. Sleds like these were used by Scott and are still used since they out-perform any modern development. Made of ash wood and lashed together without nails, they are able to flex with ease across the difficult terrain, they remain an awesome and beautiful piece of design.

'I Can See the Sea'
The shelf thins in the Hinge Zone to the point that sea water seeps in to the bottom of crevasses

Travel in each direction and striking camp takes up a whole day, given that travel, including leaving the tents is only feasible when there is good weather, meant that we had one good day out and about, which we made the most of, particularly since this is more time than most of the other groups have had. Good weather doesn't just mean not blowing a gale, any cloud cover destroys the contrast to a point where it is unsafe to do anything apart from around the campsite. Furthermore, due to a problem we headed back to base a few days earlier than planned.

Brian Ice-Climbing

What a day, however! The opportunity to abseil off large ice cliffs and then ice-climb back up in an area where few people have been before is particularly special. However, for me, travelling across the Brunt for hours surrounded by flat ice has to be the highlight, you rapidly realise your insignificance on the surface of this continent.

Walking in 'Desperation Gulch'

An unusual sight was that of rocks as we abseiled off Stony Berg. This is a large berg which in the movement of the ice stream been turned upside down, scouring the bottom of the sea bed and bringing with it a large collection of rocks; in the absence of vegetation, rocks can be particularly exciting. The other unusual sight was a pair of Antarctic Skuas over camp, though there were the occasional pairs of birds during the summer, there haven't been any over base for at least the last month.

Second Chasm Scrabble
Self-portrait with Sune- I lost badly...

March draws to a close, it has been a relatively warm month, hitting -3°C at one point with a low of -33°C, not surprising given that the sun is still around. The end of March also marks Captain Scott's poignant last diary entry on the 29th- the scrawled '...for God's sake look after our people', plagued by bad weather and a shortage of food and fuel, he died soon after.

The View Off Stony Berg Across Second Chasm

Sunday, March 11, 2007

A Fortnight of Two Halves

The last fortnight has been composed of two very distinct weeks. During the first, very little was achieved outside around base as a near constant gale blew for most of it. The latter of the two weeks, meanwhile, has been spent on night duty on the platform.

The Laws Platform in a Gale

However, prior to the onset of the prolonged poor weather, there was the annual Drewry melt tank party. The Drewry (accommodation for summer staff) is effectively a self contained building on skis, including its own melt tank for producing water from snow. (The Laws, the main platform, has its own large underground tank.) As part of the process of shutting the building down for the winter, the heat trace that is used to melt snow is turned up to produce a large warm bath and the tank hosts its annual party.

The Drewry Melt Tank Party
photos by Dave Evans

The general idea is to squeeze as many people into a small container of water as possible. The luxury of sitting in a heated pool of water cannot be underestimated particularly given that water is a limited commodity on base since it has to be dug by hand and then melted. Thirteen of us, despite the small size, managed to make it in at one time. Though, given that it was at least -15°C outside, there was more than enough reason not to get out.

Not Quite 13...
R to L: top- Tom, Me, Jules, Neil, Mark, Ant; bottom- Tamsin, Alex, Kirsty and Jim

Part of the shift to winter is the gradual disappearance of the specialised vehicles that are required for the maintenance and building work throughout the summer and are now redundant. The extensive range live on a single line that extends over 100 metres north of the garage, including large tractors, portable cranes, a cherry-picker, Sno-Cats and bulldozers, not counting the innumerable ski-doos that populate the base.

The Vehicle Line At the End of Summer

Furthermore, as the temperatures drop so more and more of the vehicles become inoperable, as a result the Vehicle Mechanic, Mat, has his hands full servicing and putting all but a bulldozer, a Sno-Cat and the field ski-doos into hibernation for the winter. However, the removal of the noisy engines (particularly the two-stroke ski-doos) means that the base reverts on a windless day to a peaceful stillness punctuated only occasionally by the gentle hum of a generator.

A D5 Bulldozer in Action
The emergency food container is moved as part of a disaster response scenario

The arrival of a blow renders impossible a lot of outdoor work as the visibility deteriorates and the contrast disappears. Though it was a benign if prolonged period of persistent 40 mph plus winds, the consequences of even this relatively mild weather is that snow not only forms extended windtails behind every object standing proud of the surface but also covers and rapidly buries objects as well. Furthermore, the snow is so fine that it will find even the smallest hole in any box or container and rapidly fill it; this can be further complicated by it freezing solid into a block of ice if it is not shifted promptly.

Working In Bad Weather
Clearing snow from the tunnel access shaft

The poor weather, however, meant a chance for me to set the surgery straight and go through the emergency medical kit, which is legion, as well as familiarising myself with the base Search and Rescue (SAR) equipment, since the pre-winter field trips have started. I leave for six days in the field in a few days time and hope to fair better than the first group, who ended up spending six days pinned in their tents by the foul weather.

Fog Over BART
The daily meteorological balloon is released from the BART platform

The second week found me doing the easiest week of night duty I have ever done. I have to admit that it struck me, particularly at about 2 in the morning on most nights, how much I do occasionally long for the bustle and pace of a busy hospital, whilst being in the thick of the action. I have no regrets about temporarily leaving it behind for a year or so but it is also reassuring to realise that I do miss it and know that that is what I want to return to. However, I am fortunate in some ways to not be involved this year in the foreseeable disaster that is currently unfolding as a result of the Government's meddling in junior doctors training.

What? No Ward Round?
Making croissant for Sunday breakfast

A night watchman is needed as there are multiple alarms that need somebody to respond to, ranging from science experiments to technical services (such as the generators and fridges) and of course the fire alarm. Given the dry atmosphere and the inflammable nature of the building, this presents a real risk hence the need for somebody to be at least half awake to deal with a problem quickly. Evacuating a building when the temperature outside is -30 and dark would be less than ideal.

Sunset Through the Platform Legs

Night duty also means a few hours of cleaning as well as three and six o'clock meteorological observations. A large amount of the data (temperature, wind speed, direction and pressure) is collated automatically but added to this is information on current weather, visibility, cloud type and coverage. This is all sent off electronically within ten minutes of the observation to the Met Office in Exeter, where along with data from around the world it is used to model weather on a global scale. My knowledge of clouds has had to improve rapidly, as has my baking given that night watch traditionally bakes all the bread fresh for breakfast.

Not Quite The Genuine Article
But not bad given that the nearest boulangerie is a decent walk in the morning

The lunar eclipse was unfortunately obscured by the single okta of cloud in the sky, however the feeling of watching the increasingly colourful sunrises over a cloudless Antarctic, knowing that there is nobody else awake for thousands of miles to disturb that quiet, is inexpressible. Hopefully the next entry will have plenty of exciting photos from a decent trip off base, as long as the weather holds.

Full Moon the Day After the Eclipse