Mike Leahy's NZ diary: Ice ice baby

Production team

Day 22 - Speed and Melt of Glacier Calculating the speed of the glacier Kathy, J and I are going to go up the glacier. This time, rather than walking, we will be taken in a helicopter. Our aim is to work out how far the glacier moves in one day. At first this sounds easy, but it most definitely is not.

The glacier, like a river, is likely to move fastest in the middle so we plan to measure its speed there. But where can we measure it from? The rest of the glacier is moving.

There are no fixed points like trees close to the glacier, and even the rocks can move so we will have to make our own reference points. In theory we may be able to stretch a wire across the glacier, make a mark below it in the ice and return next day to see how far the ice has moved beneath the wire.

However simple this sounds, the glacier is too big, too rugged and there is no way that we could fix and tension the wire. I consider cheating, and using my new GPS, but it isn’t accurate enough, and anyway it finds locating satellites very difficult from the Franz Glacier Valley. The only real option is to take a lesson from nature:

We judge distances all the time by using our eyes. If we had one eye it would be very difficult to work out distances unless we used perspective (the fact that distant objects look smaller than less distant objects).

This is very difficult (try touching something randomly with your finger using only one eye to guide it, or riding your bike through a narrow gap, again with only one eye - don’t cheat by looking at it with two eyes first because your brain will guide your finger by memory).

We find picking up tea cups (or beer glasses) easy. It’s second nature because we use both eyes to judge distances. This works because the view from each eye is slightly different. Using the different views (different angles) our brain works out how far away an object might be regardless of size.

The same principle can be used to determine the position of random objects mathematically. If we use two observation points a known distance apart, but positioned away from the glacial ice on solid ground, we can calculate the position of a stake driven into the ice in the centre of the glacier.

Each observation point represents one of our eyes but our brains will need some help in the form of either an accurate scale model, trig calculations (triangulation) or both. We decide to drive a stake into the glacier and measure the angle to the stake from each end of a baseline.

If we take the first measurements tomorrow (day 2) and repeat them (day 3) we should be able to work out how far the glacier has moved. That’s the theory, but in the meantime we need tools.

I’m no carpenter, and unlike Jonathan the tools I make are rough and ready. Even so, by the end of the day we have two tripods which can support the huge protractors that J plans to build (based on the principle that larger scales lead to improved accuracy).

We also have to work on hand warmers and I set about making an ice lens. This isn’t as easy at it sounds, because all the gases dissolved in the water have to be removed. I do this by boiling some water for a few minutes. It is then placed in an air-tight bottle. I plan to use an enamel dish in which water can be frozen on the glacier at night.

Kathy has a cool idea. A lens can be made by putting water in a balloon with a springy ring in it. Once the water has frozen, the balloon can be peeled off, revealing a lens shaped piece of ice. J is making the protractors. They look cool.

I’m still having trouble with woodwork and start thinking. Ellen gets all the biology because she is a botanist. It’s a shame that I get none; after all I have a degree in biology and environmental biology as well as my DPhil in Virology. Virology is biology too. Sometimes people forget that. On the other hand I have never been trained in carpentry. I do know how to use the tools, which is one up on some of the others though.

We leave the sawmill at about six, have a meeting at the Glacier Guiding Company at six thirty, and then have to get back to the huts for seven ready for evening filming. It’s a cool job but the hours are long. Sometimes it’s hard to find time for a shower, let alone to phone home.

Day 23 - Speed and Melt of Glacier As usual Mike and I go to Ricky’s place to get a ‘special’ hot chocolate. The other guys stop to pick us up in the Landcruiser. Ellen is sat in the front and doesn’t say a word. She is ill. Steve (the boss) is stressed. He realises that we are now a man down. It will cause big problems for filming. Must be the ‘botanist’s blight’ again.

Kathy, J and I prepare to go to the glacier. I’m a little worried. I have problems with heights, especially slippery ones. Kathy has a list. We start to check through it. Better safe than sorry.. The helicopter arrives as arranged at nine thirty. It has no storage pod for the gear. We measured the stuff up specially. It’s never going to fit in the cockpit. Because Ellen is ill things are confused. We are not ready to leave. The pilot leaves, ready to come back in half an hour.

Eventually we are airborne. The flight is one of the best so far. The glacier is beautiful. From high above it looks soft and smooth.

This couldn’t be further from the truth because the surface is wracked with crevasses, cracks and lumps which are made of rock hard ice. We land near where the helihikers are dropped off, unload some gear and walk towards the area where we are to work. Of course every movement has to be filmed so progress is painfully slow.

It doesn’t bother me. I’m hardly nimble on hard packed snow and ice - never even managed to ski or skate.

Surprisingly Kate isn’t much better. She is nervous and unsteady too. In fact she is the first to fall over - on camera - I am the second. J falls over. Five minutes later he falls again. He is struggling with the two huge protractors.

We find somewhere to put the flag in the glacier which should be visible from the solid rock. J and Kathy toss a coin to see who will put the flag in the tall pinnacle. Kathy wins, meaning she won’t be at the baseline to take readings. This is obviously no problem for us because a monkey could draw the diagrams and take the angles necessary - even a virologist/ecologist.

We move on. My load is ungainly and sways wildly as I try to climb up a crest of ice. We stop for lunch. Around us the glacier is moving. The movement is too slow to see but the evidence is all around us. A whole heap of ice plunges down a nearby ‘icefall’ while stones and rocks roll down ice slopes close to us. Above us a big rock teeters over a melting ice wall. It is sure to be gone in a few days, just hope that it doesn’t fall on us. The discussion goes on, physicists are like that I reckon. They think that they are seeking the truth maybe. Time isn’t so important.

After a great lunch we press on and take one set of measurements. For sure it’s not enough to accurately determine how quickly the glacier is moving, but at least we should get a half decent reading.

We get our kit together and prepare for the helicopter to pick us up. When the helicopter finally settles down its tail is hanging over a precipitous drop. We pile into the helicopter and head for the ‘Alma Hut’ where we are to stay for the night. The Alma Hut was built in 1922 and it shows. Whilst nostalgic, the interior is a little threadbare.

I speak to Chris (our guide) as he cooks. We are all in high spirits. Chris tells us that the glacier moves a bit like a freight train, stopping, then shifting, then settling before jumping forward again. Once it moved ten metres in three days. It can shift very quickly "a nightmare to walk on".

Day 24 -Speed and Melt of Glacier
Derek’s birthday
I didn’t have a bad night’s sleep. We weren’t allowed to drink in case we fell off of the mountain and I ended up dreaming about a road across the mountain with a pub on it. Over breakfast we talk about a book that I had read some time ago called ‘Beyond the Skipper's Road’ by Terri McNichol. It turns out that she was Chris’ surrogate grandmother when he had lived on a farm in Otago. It’s a small world. Even more remarkably, Chris’ sister-in-law had gone to school with Martin in Leeds.

The ice lenses are a nightmare. Although a wicked idea, the water in Kathy’s balloon lens hadn’t frozen overnight. Bummer! My ‘lenses’ have gas bubbles in them. Kathy uses a saltwater bath to quickly freeze the water in her balloon lens. The salt allows the water/snow/ice mixture surrounding the balloon in a dish to fall to very low temperatures - well below freezing. This time the pure water in the balloon freezes, but she too has bubbles. We don’t really have time to perfect the lenses but none the less, when sunlight is focussed onto our hands it warms us. Not enough to set fire to anything though.

The helicopter arrives blowing hard ice crystals from the snowy outcrop painfully into my face. We go back down to our measuring station on the glacier and take our readings. Keas had attacked the equipment overnight but it was still useable. J and I use a scale drawing and work out that the pinnacle we are measuring has moved one metre. Kathy uses trigonometry to give a result of 1.3 metres. There are bound to be errors in each but they sound reasonable enough.

We then have lunch. Derek asks the date. Turns out it is his birthday. Cool! There is only a little more walking to do, which is good because my feet hurt badly from an injury that I sustained while running away from an aggressive bull in India. The others come up to join us in helicopters from the sawmill. The programme is finished by about 4 pm. Our estimate of the speed at which the glacier moves turns out to be spot on. We are ferried back to Franz Josef township by helicopter. I’m tired. We celebrate. I get drunk. Cool programme!