Field work is all about “hurry up and wait”. You can plan all you like, but the weather has to play along. In Antarctica, this is made more difficult by the logistics of a sizeable but remote station — your own project, flight or other travel plans aren’t likely to be the only ones waiting for the weather. Last week, everything finally did align and there was no more waiting and we had three consecutive days out in the field!
After the required low–light reconnaissance to make sure we were on solid ground once more, our gang of six people — which included two glaciologists, two electronics engineers and two field training officers — is back on the Sørsdal again. This time we land at “Twin Lakes” which are two side–by–side lakes that, from what satellites tell us, form as far up the Sørsdal as there are lakes.
Only there are no lakes here yet at this time of year, just patches of shiny blue ice and strange sinuous ridges cracked open like bread crust in places. Off we go in search of water.
It turns out the lakes go underground for the winter; a couple of hours spent drilling holes reveal lots of water, some in water pockets, some in slushy ice. The strange bread crust ridges even turn out to have air in them! Like any normal lake in this sort of climate, ours freeze in winter only; if the lake bed is also frozen then things work a little differently.
Again, we put a camera tower up along with instruments to measure water pressure (under and above ground), ice and air temperature. We're hoping to see the full lake filling and “whatever happens in winter” cycle with our instruments. Tom and Sue, inbound on the next Basler flight, will hopefully supplement the instruments we have with geophysical measurements of what’s deeper under the surface, using radar and seismic instruments.
As if that was not enough of a good thing, we are off to Channel Lake on our third and final outing, a site we've been eyeing curiously for a while now. Satellites from previous years have again made us believe there should a lake there, but the naked eye sees only see a messy ditch in the glacier surface. Not a normal crevasse, this is a saggy dip in the glacier with broken up edges, and chunks of ice poking out at wild angles; a lake that must have drained. Here the field training officers will be in their element, I think, unsure how far we will be able to explore in the name of science (safety first).
The bark of Channel Lake is worse than its bite; the cracks at the edge are not too wide, and also refrozen. We can move around safely to explore the site, make measurements and leave more instruments. Several metres down inside the ditch, we drill more holes, and find more air and water deep underfoot, below a solid metre or more of ice. The lakes here obviously not only store water for quite a while, they also spill it every now and again. In the case of Channel Lake, the refrozen spillage is easy to see a couple of kilometres down-glacier in the form of a shiny, re-frozen surface water covering that stretches further than the lake itself. Hoping we're not here just to shut the stable door with the horse long gone, we leave more instruments to record any possible future re-filling of the lake — an uncertain but tantalising prospect — and head back to station, our own mission accomplished and the project waiting for the arrival of Tom and Sue. Just in time, it turns out: the next morning, we have word that we have to get to Casey in a hurry, to make use of a weather window to get us back to Hobart — and things that are green and smell of something other than the cold — in time for Christmas!