August - Snowblowing
Blowing snow the Rothera way
Written by Chris Jacobs and Iain Airth
When clearing a gravel strip runway in the middle of winter it is not without problems. There is of course ďThe BookĒ which contains the basics, what should be done and in which order these events should take place. Not quite the holy bible but a good, point you in the right direction, idiotís guide to the universe. I think the answer is still 42!
Before you can start to transform a sleepy alpine resort and open it up for the tourists a good and sensible thing to do is take a stroll, with measuring stick in hand; we, ďThe MechsĒ set off down the length of our snow covered meadow, probing at regular intervals along the way. The results didnít seem all that bad, the north covered in a liberal dusting of six inches, increasing steadily in depth as we approached the crossing point. Through the winter this is the only point on which people and machines alike are allowed access to the strip, this in turn means that there will only be a small area, which has been compacted.
Continuing on down, measuring as we went, there seemed to be an average increase in depth approaching 14 inches across the whole width of the runway as we reached the southern most end. Should be no problem was my first thought, if we can just get the wind to help us we should clear ďThe PuppyĒ in no time.
Having spent the previous four Antarctic summers clearing snow off a blue ice runway I have come to learn that the best results are achieved with the help of old mother nature casting a favourable eye over oneís efforts. The higher the wind speed, the greater the distance the snow will travel when blown. Of course it helps if the wind direction is favourable to the one in which you want the snow to go. In this we were assisted greatly, not only by the wind but the lack of sea ice, instead of snow now building up around the perimeter it would just float off and not return.
Above: Blowing twards the sea - Click to enlarge.
So, the big day finally arrived, Holy water (Tea? milk no sugar!) was spilled over the machines, which quickly froze. Then with all preparations made, machines all hitched up, it was time to get it on! Although many years since Iíve played like many a small child, memories of school sandpits, excavating the exact spot where some budding athlete is shortly to land in the hope and belief that another world record is about to be smashed. Here we are, many years on using the real thing, no bucket and spade in sight of Weymouth Pier (an amusement arcade standing on spindly steel legs and loosely connected to the land somewhere off the south coast of England) but ďThe Real DealĒ.
Climbing those steps up into a comfortable heated cab was a welcome escape from the chilled air outside. Iain made good progress leaving the garage and crossing over to the hanger in his machine; this changed slightly when as the depth gradually increased he encountered the three-meter high drift running parallel with the hangar doors. The main problem that we faced was not in the actual clearing of snow but in transporting it far enough away that it would not cause future headaches and accumulation.
Above: Blowing the first cut towards the hanger - Click to enlarge.
The decision was made to remove the blowers and continue with front mounted buckets, large enough to accommodate a small family car and transport the snow to an area where a bulldozer was able to push this out, over the beach and onto the remaining thick sea ice. This might seem to many a little dodgy, fortunately the beach shelves off quite gently so as you gradually move out from the shore you end up compacting the snow, binding it together and forming a pretty bomber surface whoís base is following the contour of the sea bed.
Above: The D4 pushing snow onto the sea ice - Click to enlarge.
This worked really well, yes it was definitely going to take a great deal longer but the main and most important thing was that the surrounding area around the hangar and apron would be level. An added bonus was the ability to share the driving with other team members, to draw on those with previous experience and those that were eager to learn. Just because youíre a computer programmer, a plumber or scientist doesnít mean that you canít operate a large and expensive piece of machinery. Itís always a surprise to us here in the workshop and those that have a go, how many people can have a talent for this kind of work without realizing it.
The runway itself was actually quite straightforward in the end; Mother Nature dealt an excellent hand, providing wind when it was needed and beautiful sunlit mornings when a lift was most welcome. As some of the pictures show, with these two machines running up and down we were able, the first time, to get the gravel strip cleared in under 24hrs.
It was certainly tiring but also very rewarding, with the machines working together in perfect harmony, not quite line dancing more like come dancing as we wiggled along catching those occasional bits that the other had missed. I think one of the highlights for us both was whilst working at night, switching off the work-lights and view a brief light show, similar to St Elmoís fire that could be seen emanating from the tip of the blower chutes, the result of small stones being fired out through the machines. This is one of the many reasons why there is a restriction on how far you should be from these puppies with a camera whilst they are working. A snow blower doesnít know the difference between snow, gravel and small rocks, if itís gone in the front itís going to be coming out again with a major increase in speed and force, just imagine being stung by a wasp the size of a large robin!
Above: Blowing in the sunset - Click to enlarge.
With the bulk of snow now removed from the runway it was still far from ready to accept an airplane, the occasional light ridges left also had to be removed. For this I found that by using the bulldozer blade and skimming the surface with it angled to the side, creating a lovely swath, the strip could then be graded. Followed by one of the tractors using a light-grooming blade the surface came up pretty well with few ridges and undulations.
Still not perfect though, the finishing touch was to re-roll the surface, as in places it had been noted that with the return of the sun and the now disturbed top layer, soft spots were appearing. It was hoped that by compacting and blending the fine snow still present with the loose gravel it would melt and consequently refreeze providing a firm and uniform crust. The end result, benefiting the aircraftís braking performance and then later when it was due to leave reduce the distance required to take off.
It was with real disappointment that with the job all finished, the runway and apron cleared, the area around the hangar graded and levelled, it snowed again. During the night prior to the Dash 7ís arrival we had a light dusting which continued through into the morning, still not enough to prevent itís landing but now we had lost our clearly defined black strip, which would have been an extra aid to the pilots.
About a month has passed us by after we carried out all this work, it still looks good, minimal accumulation and with a little luck should make the task easier in six weeks time when we have to do it all over again, prior to the return of summer. We still have quite a lot to do; all the machines need to be checked over again, the odd leak rectified here and there. The main thing you learn down here is that itís better to keep checking things, keep everything in as good a condition and reduce as much component failure as possible.
There, that wasnít all that strange was it?
By Chris Jacobs and Iain Airth