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