Aoraki Mount Cook

Out of our original top 3 favourite glaciers to check for ice cores there was still one left to go. This was the Baker Glacier, visible clearly from our previous site on Mount Hutton, almost directly across on the other side of the Murchison Glacier Valley. Baker Glacier is relatively low altitude at 2360 metres. None the less, because it is also east of the Main Divide, it will have relatively low accumulation rates and, with a depth of about 70m, potential for a longer core than we got on Mount Hutton. However the radar images showed a very strong reflector at about 30 – 40 metres, possibly due to the presence of water or rock debris about half way down, a potential indicator of trouble ahead. By now we had our gear preparation down to a tee, and were set for another blitz approach to get in and out before impending bad weather trapped us in. We flew in to the upper part of the Baker Glacier, directly opposite the imposing cliffs of the East Face of Malte Brun. Almost immediately an ice avalanche rumbled down the face, I guess as some sort of greeting to us.Within a couple of hours the drill was set to go and the tents were in place. After getting past the initial surface snow, we were soon pulling up nice quality ice cores, full of air bubbles trapped within a matrix of ice. As usual, Uwe helped Xinsheng at the drill control box and I worked with Dan bagging, labelling and packing the cores. Evening fell whilst we continued working, expecting to go on until the early hours, all being well with the ice. However at about 8.30pm, with 30 metres of core recovered, we suddenly started getting wet ice again. The strong reflector layer in the radar images was explained. One further drill section confirmed that the ice was getting wetter and Xinsheng again called a halt to the drilling. We were to get some sleep after all. In the photo, Dan is holding the final section of ice core that we drilled. We decided to pack up as much as possible in order to make a swift departure in the morning. Once the net load was more or less organised, we got out the dice and played a game of Zilch, sitting on ice core boxes with our head torched on. During the night occasional avalanches roared down the cliffs in the dark. A beautiful sunrise lit up the scene as we got ready for our final helicopter ride down to the valley floor.

After yet another day of sorting out and preparing our gear, the weather forecast looked quite promising for a few days. We decided to fly back up to Mount Hutton and drill non stop until we either came to bedrock of had to stop for other reasons, such as water in the ice. The four of us -Xinsheng, Dan, Uwe and myself, again flew up to the peak. It is a spectacular location with steep drop offs falling hundreds of metres down on all sides. Once up there you are committed! A sky of whispy clouds stretched above Mount Cook . Our heli put us safely on the landing spot, with our emergency survival gear (tents, food and extra warm clothing). This is standard procedure just in case something prevents the second load from being delivered – a sudden change in the weather or problems with the heli. Whilst the other three went up to the drill site (the same place that we had drilled our 10 metres core already), I walked across to a beautiful horizontal scoop in the snow that we had chosen for a campsite. Although the weather was sunny and calm, I made sure that the tents were well attached to the ground with snow stakes and shovel loads of snow on their snow flaps. We wanted to be able to go to bed very late without worrying about a change in the weather. By about lunchtime I could hear the humming of the generator at the site about 200 metres away telling me that the drilling had started. Once finished with the campsite I walked up to the others, feeling the effort more than usual due to the altitude. The drill site was now top notch. We had an upgraded snow wall to keep the wind off us, the drill pit was enlarged and the hot plate was on, melting snow for hot drinks and food. Uwe had decided to start a new core right next to the previous one to see if we could get a better quality first 10 metres that was less broken into sections than the first had been. Progress was very good, with no technical problems. The ice was mostly very bubbly glacier ice, immediately below this year’s winter snow. At the top there was a distinct layer of small pebbles and grit, but below that we saw little evidence of summer dirt layers. Sometimes there were clear areas in the ice, suggesting melting and re-freezing, but we found it difficult to interpret the age of the ice or what its features were telling us. Is it a remnant of old ice or all quite recent? Only the later analysis will tell. Uwe was measuring the ice temperature in the cores, which stayed consistently below freezing at about – 3 deg C. This was very promising! We had never drilled ice below 0 deg before. At last we had found some accessible cold ice in the Southern Alps! Once the routine of drilling and bagging the cores was established, there was time to look around, take pictures and chat. As the drill gets deeper, it takes longer and longer to winch up the core each time.  I took advantage of the opportunity to take an ice axe and climb the short distance up to the summit for a view from the top.Taking care not to slip I peered down the East face – a very long way down! After a few minutes I carefully cut steps back down off the summit to rejoin the others. The photo shows my tracks from near the top and you can see the drill site and our tents in the distance Just around 9pm we started to find bits of gravel in the ice cores at about 33 metres depth. Then suddenly Xinsheng said “Is finished!” – We could hear the drill clunking against rock down below in the hole. The first ever New Zealand ice core drilled to bedrock had just been drilled, a humble 35 metres from the surface.

Today we flew up to our highest planned drill site on Mount Hutton. Yulan stayed behind, and with us instead were Tom McRae and Ron Madden from TV1. Because of the prospect of poor weather forecasted for tomorrow, we had decided to do a rapid reconnaissance drill only. If the results proved to be good we would come back with a better weather window to drill deeper. Mount Hutton is relatively remote – on the eastern side of the Park in the Liebig Range. We hoped that with the higher elevation and the location some distance away from the main divide, we would get a better preserved and longer climate record. Our radar survey showed a depth of only 50 metres of ice, but perhaps 50 metres of thinner layers would be as good as 100 metres of thicker ice further to the West (such as on Annette Plateau). The flight up was spectacular the icy clouds producing a nice sundog spectrum . Mount Hutton has a small glacier on top. It has a ridge running straight up the middle, and our drill site was about 3/4 of the way up the ridge from our landing site at the bottom. I went a head with Uwe to find our spot and start digging in. The winter snow was only 1.5 metres deep here (as opposed to 4 metres on Annette Plateau)Tom and Ron were interested in what we were attempting, asked lots of questions and interviewed us for their news programme. When they left at about 1pm, Dan went down with them, leaving Uwe, Xinsheng and myself. By 4pm we finished drilling having got down to 10 metres, with very nice, bubbly glacier ice immediately below the top surface snow. The heli arrived and flew away with the net load of gear, then returned half an hour later to pick us up. The evening light was beautiful across the big peaks of the Southern Alps.

Dan and I got up early and each went of for a walk around the glacier. I climbed up Mount Annette and then returned through the wind scoop. The plane arrived and by the time it was fully packed there was no room to fit both of us in! I decided I would be happy to walk down to the village. I set out with a pair of bamboo poles and snow shoes. The way down involved crossing some steep slopes, with wonderful views across the Mueller glacier and I was happy when I reached the valley floor where Uwe had come to pick me up. The photo shows the tracks I followed across the mountainside.