A 'Testing Blow'

The Dive Team Hard At Work

Continuing with the sea ice theme from previous posts, on Wednesday I went to help the Dive Team while they were cutting a hole in the ice for a new dive site. Once the blocks had been cut with the chainsaw, we set about attaching ice screws, clipping in ropes, and hauling them out. It is surprising how heavy a half-metre block of ice is, and it is hard to handle when you're on ice, with little grip, and a freshly cut hole to fall into if you slip! With the holes cut, covered with a wooden board, and marked with flags for safety, we decided a little sit down was in order. The Dive Officer is a big fan of Lego (as evidenced by his recent Lego Death Star purchase), so he took charge as we assembled the various blocks into an armchair, using the hand-saw to neaten rough edges as necessary and slushy snow to cement any spaces and sculpt rounded edges. This was shortly followed a predictable fight over who got to sit in the seat while we posed for photographs!

Saturday was too windy to go out to play, although this was no bad thing as it provided the 'testing blow' we needed to prove the strength of the sea ice for more distant travel. I worked on my blanket, reaching the half-way point - 59 squares knitted, 58 squares to go! Of course, there is the small matter of sewing the strips together, knitting on a border, and probably backing it with fabric, but as far as the squares are concerned,  half-way!

Sea Ice Break Out

Sunday was even windier (gusting up to 74 knots!), but we were stirred from knitting and pool-playing by an 'all stations' radio call from a couple of people who had noticed that the sea ice was blowing away. The 'testing blow' had tested one blow too far, and we all got to watch a sea ice break out. Everyone rushed to get dressed up in lots of warm gear and headed up to the Cross to watch the spectacle, and what a spectacle it was! A strong Westerly wind was creating enough sea swell to crack the edge of the ice, and was then blowing the chunks away from the main body. This meant that the crack line gradually worked its way further and further into the ice sheet. We sat there (sitting, because with the wind speed standing wasn't an option!) and watched the crack line move back about 500m in half an hour. Our beautiful armchair broke free and went sailing off; with the direction and speed of the wind, hopefully it will make it all the way to San Martín Base and the Argentinians can make some use of it!

Armchair Traveller

Killingbeck Island

Killingbeck Island

With the recent cold temperatures helping to form and stabilise the sea ice around Rothera, on Saturday we decided to strike out for Killingbeck Island. There is a photo of Rothera Point in a previous blog post, and Killingbeck Island is in the middle far left of the picture, about 2 km out to sea.

We started out from North Cove and made out way around the North end of Rothera Point. As we had drilled this area recently we could move fairly quickly. When we reached new ice which needed testing, two of the GAs struck out ahead so the rest of us could travel along more leisurely, admiring the icebergs and taking photographs. On our arrival at Killingbeck Island we were rewarded with a visit from three Adelie penguins who came running up to us. I am sure they thought we were penguins too as they ran very fast until they were about five meters away, and then stopped, looked at us with a disappointed expression, and then waddled slowly away. We also had a lot of fun getting on and off the island, as there was broken ice around the island caused by the tide lifting the sea ice up and down. It had formed chunks which we had to move across, a bit like lily-pads on a pond.

Killingbeck Island was at the limit of the current stable ice. The photo of the island shows the thicker white ice which was about 30cm thick, and a small amount of newer darker ice, which was only about 10cm thick.

Adelies Saying 'Hello'

Doc On The Ice Lily-Pads

Rothera Point Sea Ice

A Chocolate Cake Tool Kit!

Wednesday was our generator mechanic's 40th birthday. Having seen photos on Facebook of the wonderful cakes his wife at home makes, we felt we ought to try to make his 40th cake something special. A team effort, admittedly mostly lead by the chef, resulted in a spanner, hammer, nut, grub screw and a bottle of WD40, all made from chocolate cake and iced with molten chocolate. We couldn't find 40 candles, and even if we had, we would probably have set the fire alarm off, so we settled for 11 baby pink ones instead! I 'helped' clean up the icing bags and excess icing a few hours earlier, and couldn't face actually eating any cake, but it disappeared suitably quickly!

Testing The Thickness Of The Sea Ice

This afternoon the clouds cleared and the wind dropped, so a few of us set out the test the thickness of the sea ice around base. We set out to go around Rothera Point, but were prepared to get back onto land and come back to base that way if necessary. To test sea ice, one drills a hole all the way through, and then inserts a very technical stick which has a lever on the end. You pull the stick back up until you feel the lever catch on the underside of the ice, and then read the depth off the stick. The ice has to be a minimum of 20cm thick for people to ski on it, 25cm for walking, and so on upwards to 157cm to land a Hercules! We had 30-40cm thickness all the way, so successfully made our way around the point. It was very strange seeing the land from the ice, and to be able to look up at the wharf. The ice feels so substantial, but six months ago I was bobbing about here in a boat doing my crew training.

This evening one of the GAs did a slide show (yes, slides, with a whirring motor, genuine clicky noises and everything!) of a climbing trip he did in his younger days around the USA which was a nice change to the usual knitting, DVD watching or pool playing. On the knitting front, the dinosaur is progressing nicely. I have changed the pattern so that I am knitting in the round with the legs and plates knitted on, as I didn't fancy sewing ten stegosaurus plates down its back!

Biscoe Wharf From The Sea Ice

Ice Ice Baby: Two Cold Photographs

Two recent photos of what happens when you have a few days at around -20°C (-6°F).

Rothera Point surrounded by sea ice as far as you can see. In Hangar Cove at the bottom left of the photo the ice is so thick now that it is almost indistinguishable from land.

Up at the ski area we had retreated to the caboose for a cup of tea. I swilled my mug out with some more hot water and threw it out the door. The chippy suddenly got very excited as he had noticed that as my hot water met the cold air, it froze and created a cloud. Everyone ran back into the caboose to get more mugs of boiling water to throw in the air.

I've shamelessly cut and pasted from the internet, as they have worded it better than I could:

First, the near-boiling water is already close to becoming steam when it is thrown into the air, which means that the water molecules are much closer to evaporating into the vapor state than they would be if the water were cold.

Second, the act of throwing the water into the air causes it to break up into tiny droplets. The water that was contained in the cup (which originally had a relatively small surface exposed to the air) now experiences a tremendous increase in the total surface area exposed to the air. This situation helps to speed up the evaporation process (evaporation is the process of turning from a liquid to a vapor).

Finally, very cold air typically has a low humidity level (that is, a low amount of water vapor present). This is yet another factor aiding the transition from liquid water, to water vapor, to ice crystals. At sufficiently low temperatures, this process seems to occur almost instantaneously. 

Cold water is more viscous than hot water, so doesn't separate and spread out as efficiently as boiling water does, which is why it doesn't happen with cold water.

Antarctic Water-Skiing

Now that we've had sufficiently prolonged cold temperatures and a calm period, the sea ice has thickened and solidified enough for us to go onto it. The dive team and GAs have been monitoring it for about a month while it has been too thick to use the boats, but not thick enough to walk on, as they are keen to get back in the water to carry on with their science experiments.

To travel on sea ice we wear a dry suit and skis. We also take a sledge with spare clothes, and rescue equipment. Sliding onto the ice was a strange feeling, but it felt reassuringly substantial once I'd gone a few meters away from the crumbly bit at the edge where it gets broken away by the rise and fall of the tide. As we went out further it was interesting to look back at base, and also very cool to see the icebergs trapped in the ice. We reached an area of newer ice which was being monitored, and the GAs drilled a hole and determined that ice not to be thick enough yet, so we skirted around the edge past the runway and into a different cove. This was where the dive team had been practicing with the chainsaw, so we each had a go at jumping in, splashing around and the trying to get back out. It really wasn't as cold as I'd feared because the immersion suit and the dry clothing underneath keeps you warm, but my hands were a bit cold. We carry ice axes in case of falling in, so used these to dig into the ice to pull ourselves back out again which wasn't too bad as the air trapped in the suit makes you very buoyant anyway (hence me looking rather fat in the photo - I haven't actually put on 20 stone!).

Wednesday afternoon was the equivalent of a family trip to Tesco. Food is stored in a few different places around base, so that if there is a fire we don't lose the whole lot in one building. First we went to the deep freezes in Fuchs House and formed a human chain to pass out chips, scampi and chunks of Argentinian beef so large that I'm sure if we'd let them defrost they could have just walked over to the kitchen by themselves. Next was the food store in Old Bransfield for 20kg bags of pasta, 2.5kg tins of tomatoes, enough bread flour to sink a small battleship, and other assorted dry goods. Everything was loaded on to sledges, which were then pulled by skidoo over to Bransfield House where it was stored according to the dictator's chef's instructions.

Most excitingly, we also found 2 fugitive tins of spaghetti hoops lurking at the back of a shelf. Roll on Sunday morning!