Shovelling Snow…
Wind chill is a major hazard in Antarctica – even a relatively mild -10 degrees can become dangerous when the wind gets up. The wind can also get the snow skating across the surface of the ice – the faster the wind, the more snow it is capable of moving. When the entire plane of ice, as far as one can see, is subjected to this type of wind, it can be quite a beautiful sight. And all the more so when it is lit by late and low evening light: the surface becomes a sparkling and moving luminous hazy carpet.
We've just had ~48 hours of continuous wind like this, with the snow skating across the surface for the better part of Friday night through Sunday afternoon. A few steps away from the camp brings a fairly unique perspective – standing amid a wide, shallow river of snow, and the only part not in constant movement as far as the eye can see is within the wind shadow of the camp itself. The wind shadow stretches for several kilometres, leaving a narrow wedge of undisturbed surface.
While a truly lovely experience, such conditions mean that work outdoors and away from camp is not safe. So, while the wind blows with enough force to rattle the containers, we occupy ourselves with the many tasks and observations that can be completed indoors. And this is where the container camp comes into its own.
Our 'hydrolabs', with holes in the floor that allow access into the ocean from inside a warm container, allow the oceanography to continue whatever the weather. In this case, we were able to complete a couple of 'CTD casts'. This means sending an instrument all the way from the ice surface to the seafloor, three times over, taking readings of Conductivity ('C'), Temperature ('T'), and Depth ('D') the whole way. In this way, we can develop full depth profiles of Temperature and Salinity throughout the water column. Slight shifts between the layers tell us about the history of the water – where it ultimately came from and what might have happened to it on the way to our measurement site.
Another exciting activity for 'inside' days has been to try out our new ROV (Remotely Operated Vehicle) from one of the hydrolabs. This little machine is very useful for giving us 'eyes' on our equipment suspended in supercooled water so that we can gauge how much ice has grown on it. It could also have been useful for recovering our mooring – although only intended as a back-up option, and thankfully not required this time!
Meanwhile, outside, the wind continues to blow and move the snow around. The presence of our containers causes the wind to slow down enough that its load of suspended snow drops out. This can lead to large 'snow drifts' around our containers, vehicles, and anything else we have lying around. This quickly becomes problematic when the wind direction is such that the snow drops out immediately in front of the container doors, potentially leaving us stuck inside. Thankfully this only happened to a very small degree this year, and for the most part we could just wait until the wind died down to begin the tidy up.
We did have a similar event last year, with a slightly different wind direction relative to the layout of the camp. In that case, the snow was deposited so that it built up against the doors of the containers, which, if we'd done nothing, would have trapped us inside. This led to a constant battle with the wind: we shovelled continuously for a day to retain access to the containers. But the wind kept blowing it in again as fast as we shovelled it away.
When it was all done, the snow drifts had built up to more than half the height of the containers, and we had maintained a 'trench' connecting the line of containers. But there's only so much we can achieve with a shovel. It was time to call in Johno with the PB300!
Sent from Iridium Mail & Web.
We've just had ~48 hours of continuous wind like this, with the snow skating across the surface for the better part of Friday night through Sunday afternoon. A few steps away from the camp brings a fairly unique perspective – standing amid a wide, shallow river of snow, and the only part not in constant movement as far as the eye can see is within the wind shadow of the camp itself. The wind shadow stretches for several kilometres, leaving a narrow wedge of undisturbed surface.
While a truly lovely experience, such conditions mean that work outdoors and away from camp is not safe. So, while the wind blows with enough force to rattle the containers, we occupy ourselves with the many tasks and observations that can be completed indoors. And this is where the container camp comes into its own.
Our 'hydrolabs', with holes in the floor that allow access into the ocean from inside a warm container, allow the oceanography to continue whatever the weather. In this case, we were able to complete a couple of 'CTD casts'. This means sending an instrument all the way from the ice surface to the seafloor, three times over, taking readings of Conductivity ('C'), Temperature ('T'), and Depth ('D') the whole way. In this way, we can develop full depth profiles of Temperature and Salinity throughout the water column. Slight shifts between the layers tell us about the history of the water – where it ultimately came from and what might have happened to it on the way to our measurement site.
Another exciting activity for 'inside' days has been to try out our new ROV (Remotely Operated Vehicle) from one of the hydrolabs. This little machine is very useful for giving us 'eyes' on our equipment suspended in supercooled water so that we can gauge how much ice has grown on it. It could also have been useful for recovering our mooring – although only intended as a back-up option, and thankfully not required this time!
Meanwhile, outside, the wind continues to blow and move the snow around. The presence of our containers causes the wind to slow down enough that its load of suspended snow drops out. This can lead to large 'snow drifts' around our containers, vehicles, and anything else we have lying around. This quickly becomes problematic when the wind direction is such that the snow drops out immediately in front of the container doors, potentially leaving us stuck inside. Thankfully this only happened to a very small degree this year, and for the most part we could just wait until the wind died down to begin the tidy up.
We did have a similar event last year, with a slightly different wind direction relative to the layout of the camp. In that case, the snow was deposited so that it built up against the doors of the containers, which, if we'd done nothing, would have trapped us inside. This led to a constant battle with the wind: we shovelled continuously for a day to retain access to the containers. But the wind kept blowing it in again as fast as we shovelled it away.
When it was all done, the snow drifts had built up to more than half the height of the containers, and we had maintained a 'trench' connecting the line of containers. But there's only so much we can achieve with a shovel. It was time to call in Johno with the PB300!
Sent from Iridium Mail & Web.
Comments
Post a Comment