Warm weather welcomed us to our fourth ice station. This can be an indicator that a storm is coming in, and our subfreezing heat wave was no exception. Predictions suggested the weather would degrade late in the evening of our arrival and become blizzard conditions by the following morning. It was decided that the Aurora wouldn’t be properly moored to the floe in case the ice broke up during the blizzard. The engines were kept on a slight throttle to push the ship into the ice. While not anchored there, this allowed us to “go with the floe,” a quote attributed to our voyage leader.
We stepped off the gangplank into balmy -12 degree C weather with almost no wind. People were immediately seen shedding layers of clothing, attempting to find the balance that would keep them warm but not sweating.
We found a good site for our experiments and promptly started shoveling, during which even more layers of clothing disappeared. The area we chose for experiments had about 40 cm of snow that had to be cleared before we could work. We were warm and happy, especially when compared with the last few ice stations. We worked well into the evening, taking advantage of a rare combination: ice and weather well suited for our experiments.
The blizzard arrived a little later than expected, and the entire next day was spent inside the ship. High winds around the ship create interesting sounds that vary based on location. The wet lab contained a low vibration that seemed to increase with the gusts. Whenever an outside door was opened the doors in the stairwells whistled as they attempted to release the new pressure into corridors beyond. A low hum can be heard on the bridge as the air vibrates windows and doors. A soft rattling filled my cabin when the wind hit its peak.
During high winds, we remain onboard the vessel. The winds themselves make working conditions miserable, but this is not the primary reason to remain aboard. During high winds the snow blows around, creating very low visibility. Teams on the ice can no longer be seen, so the bridge cannot react properly to changing events on the ice. High winds typically prompt the ship to stop moving as well, as low visibility makes it impossible to plan a good route through the ice. I have included a photo of a flag marking our worksite.
The photo was taken from the bridge in blizzard, or “blizz” conditions. We were one of the closest teams to the ship, and our flag was only intermittently visible during the storm. You can see, from the other pictures of our worksite, how close to the ship we actually were. Ken was kind enough to give me a photo looking off the back of the ship. The water nearby appears to be protected from the wind by the ship, but if you look at the ice edge you will see how quickly everything becomes indiscernible shades of white in a storm.
We awoke curious if our ice station still existed after the blizz. The station did exist, but several new cracks had appeared. Our work area was initially very restricted while the bridge watched these cracks, but after a few hours we were allowed to expand to approximately the area we covered before.
The blizz provided a good deal more snow loading than we experienced the first day out, which resulted in an interesting condition for one of our experiments. One of the measurements we make during our experiments is the “freeboard,” which is the distance between the top of the ice and the top of the water. Since sea ice is less dense than water it floats slightly above the water’s surface. The freeboard we measure is a positive number when the ice surface is above the water surface.
The additional snow loading on our site caused the ice to be depressed into the water. Holes drilled through the ice would flood the ice surface, creating ponds of seawater as deep as 8cm. Since the water surface was above the ice surface the freeboard we measured was a negative number. Over time the seawater will naturally push its way through the brine channels, cracks, and around the edges of the ice, causing snow melting and slush development. This slush will refreeze, causing the ice to grow upward in height. This was exciting for me to see, as I have not actually encountered negative freeboard before while doing field research, even though it accounts for much of the Antarctic ice pack growth.
In what has become a common theme on this trip, we again were approached by curious wildlife. I imagine they were wondering why we were creating puddles in their pristine snow. A trio of emperor penguins made their way through camp, and a lone adelie kept watch from a distance. A pair of seals were also seen wandering around the camp. I haven’t yet located pictures of the two seals together, but Ken apparently has some fantastic video of them.
It is amazing to see the curiosity our presence generates. Anecdotally, several people aboard have commented that more wildlife has been seen in this region than is normally encountered this time of year.
During the day we received updates from the bridge suggesting that the ice looked less favorable, and all stations should plan accordingly. New pressure ridges in the distance suggested that the floe had broken up considerably, but was locked in place by other ice pieces around it. Our ice floe was broken, but was safe to operate on until other ice moved to provide it a space to expand into. A close eye was kept on the horizon for new blue bands of water, evidence our broken floe was no longer being held together from the outside.
These bands appeared near sundown so all equipment was removed from the ice.
Around midnight our floe spread apart, leaving us among littered pieces of what had been our most productive worksite. Although Ken, Christian, and I would have loved another day at this station, other groups had completed the work they were able to do here, so we pushed on.
At the moment we are still headed South. We are travelling through rough terrain that sometimes requires us to back up and strike the ice a few times to break through. We plan to spend some time in the fast ice around the continent , but are not absolutely certain this will be possible. Our forecast for the end of the week is poor, potentially slowing our movement and preventing helicopter operations. There has been talk of another ice station before we try to make our way into the fast ice. Some of the ice we are turning over is starting to look brown underneath, a good sign for the biology team.
During a mid-voyage briefing the biology teams advised us that algae cells that had been found were largely in an inactive state. They indicated there is great potential for cell growth here, but many of the cells appear to be in “winter-mode.” A lot of this may be due to the very cold weather we have been receiving. The biologists are interested in seeing if there will be any change to this state during our return, as we will be headed north at the same time the area is undergoing spring warming.
The biology teams aren’t the only ones interested in seeing warmer weather.
The warmth we have known recently sure beats the bitter cold we have been working in. With any luck we will be able to push our way into the fast ice without problems, and stay for a few warm days. Leaving the fast ice will surely be bittersweet. I am sure we will all feel the pressures of time, actively limiting the amount of data we can collect. On the other hand, even bitter cold can’t be that discouraging with the knowledge that we are headed North, to warmer water, warmer ice, and ultimately to the warmth of home.