|Abseiling into the Moulin.
|Inside the ice cave.
This moulin/tunnel system had been surveyed every few years since 1998, and was found to be constantly evolving. This year the moulin was about 40 metres deep. After which we were able to follow the ice tunnel for about 300 metres before it was blocked by water. Previous surveys have shown that the tunnel had many steps and pools, but this year there was only really the major one step within the tunnel.
As well as surveying the tunnel using the traditional method using a compass and a laser rangefinder, the Aberyswth team were interested in using use a laser scanner to build up a detailed 3-D image of the tunnel. Laser scanners had previously never been used in an ice-walled channels. This technique would give a much finer spatial resolution data set than has previously been achieved, from which to analyse morphology change after one melt season (the team plan to return and re-surveying the channel again next year).
|Telly Tubbies do science! Jayne doing some survey of the surface of the glacier close to the moulin on a chilly day.
|The view from the abseil into the moulin
We were hampered a bit in the surveying by the weather. As well as stopping us going out that day the mild wet spell mentioned in the last blog post also released a bit of water. We failed to get up to the glacier the next day by rivers of slush. The next couple of days we made it up there, but a little water dribbling into the moulin made the abseil and jug out very damp, unpleasant and awkward due to the ropes icing up.
The next day the temperature dropped to about minus 20 degrees C(being a geek I brought along my thermometer to measure these things, but unfortunately the batteries stopped worked in minus 18). This caused a couple of problems, firstly the scanner struggled a bit at these low temperatures. Secondly, thermal contraction of the ice walls of the moulin meant that it started exfoliating, and falling off the walls, which restricted access.
Despite the problems with the weather, and we managed to get a fair bit of scanning done, and the the early results are promising. They as planning to return next year to re-scan the channel. I hope I can get involved again