The sea-ice has been on our doorstep for a good few weeks now. We have watched it gradually grow, inexorably swallowing up the open water as the winter deepened and the temperature dropped. We have had to wait patiently to take our first steps on the ice, holding on for the ideal conditions to mitigate the very real risks.
This week our field assistants deemed that the local ice was thick enough and strong enough for us to venture out for some training. Therefore on a bitterly cold, still, clear afternoon four of us gathered in Fuch’s House, the field equipment store, to get suited and booted and start our induction.
We started by going over all of the kit that must be carried on the ice – first, a bulky waterproof boating survival suit must be pulled on, with your head and arms squeezed out of the tight rubber cuffs like toothpaste out of a tube. Then on with a harness, used mainly as an easy-grab handle for someone else trying to pull you out of freezing water. A personal throw-line is clipped on, along with an ice-axe and a pair of tent-peg sized metal spikes called warthogs that can be used to claw your way out of trouble. In your hands goes a bog-chisel, a substantial wooden pole with a metal chisel on the end, useful for prodding the ice (bog-chisels go everywhere in Antarctica – useful for pretty much everything, they are the polar equivalent of a pocket-knife. You can guess from the name what their primary purpose is in the field!). Finally, onto our feet went skis and seal-skins, which are ideal for travel on the ice as they spread your weight out over a greater area.
That’s not the end of it – the group leader also tows a lightweight sledge containing yet more equipment. The essential ice-drill and measuring pole go everywhere with you; emergency dry clothes are a must, as are the usual GPS, map and compass in case the weather closes in. Eventually, we were packed and loaded and ready to head out into Hangar Cove, the well-established sheet of ice to the north of the base.
The first hazard to navigate is the tide-crack, a weak spot formed where the mobile, floating ice meets the stationary shoreline. As the tide moves up and down, the ice fractures and can form fissures up to a couple of metres wide which can be hidden under the surface snow. Fortunately, the crack that we crossed was narrow, and responded favourably to some vigorous poking with a bog-chisel (i.e. it didn’t give way!).
Once on the ice, it was fairly easy going on ski. Initially, there was a lot of trapped brash ice to avoid, some like chunks of glass up to a couple of metres across that potentially create a weakness in the surface. As we got further out, the base was hidden from us by some huge grounded icebergs. Although the temptation is to go and explore them, the risks are great – if they are grounded, then they will have tide cracks around them. If they are still floating, then they can roll unexpectedly, shattering the ice around them and tipping anybody nearby into the freezing water.
Once every couple of hundred metres we stopped to drill a hole with the battery-powered hand-drill. Happily, all of the ice that we were crossing was deeper than the substantial drill bit, so required some supplementary prodding with a hand-powered auger. With the hole complete, we poked down a measuring stick and clocked thicknesses of over 50cm – almost enough to land a plane on! All of this information is carefully noted and recorded, along with the GPS location – this historical data is vital for judging the safety of the conditions year by year.
With the daylight still in short supply, we soon had to turn round and head back to base, with just one small aspect of the training yet to be completed. The marine team had already seized their chance to chain-saw a couple of dive sites in the cove, leaving us with a couple of handily-placed, human-sized ice-holes. Rather than sensibly passing these by, we tentatively stripped off skis and boots and leapt into the freezing water, to try out the challenge of clawing your way out of a slippery ice-hole as your appendages rapidly turn numb! Happily, we all escaped and survived the trip home afterwards, albeit now covered from head to foot in a thin veneer of ice.
This was probably the best excursion I’ve had yet from the Rothera. We’ve now lived here for over 9 months, during which time our horizons have been very limited. It’s difficult to explain how liberating it is to suddenly view the base from a completely different angle, to gain a different perspective. We can only hope that the ice sticks around for long enough to get many more trips in.