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Antarctic conservation

3 Posts tagged with the snow tag
2

Dig, dig, dig!

Posted by Conservators Nov 28, 2012

Author: Jana

Date: 12 November 2012

Temperature: -12 °C

Wind Speed: 20 knots

Temp with wind chill: -38 °C

Sunrise: n/a

Sunset: n/a

 

One of the first tasks that we usually tackle when we arrive at the historic huts is to remove some of the massive amount of snow that has accumulated around the buildings during the  winter.  At both Shackleton’s hut at Cape Royds and Scott’s hut at Cape Evans, drifting snow piles up each year in the lee of the buildings, burying artefacts and pushing up against the walls of the structures themselves.  If this snow is left in place, it can turn into a thick layer of ice that becomes nearly impossible to remove, or it melts slowly in the summer sun, which can cause water damage to the walls of the buildings and to the objects sitting outside.  That’s why we make sure to dig it out while it is still in a perfectly snowy, shovel-able state! 

It usually takes several days of dedicated digging to remove all of the snow in question: we take turns hacking away at the deeper parts of the drifts or gingerly brushing where we know the artefacts are buried, and then we haul all of the loose snow by wheelbarrow or sled away from the building so it can melt where it won’t cause any damage.  As anyone who has shovelled out their driveway after a snowstorm knows, it is hard work wielding a shovel all day long, and we definitely feel like we’ve earned our lunches on digging days!photo 1.JPG

Snow on the north side of Scott's hut upon our arrival

photo 2.JPG

A day's worth of digging got us this far!

0

Sun, and Base Duties

Posted by Conservators Aug 30, 2011

Author: John

Date: 27 August 2011

Temperature: -11.2oC

Wind Speed: 22kts

Temp with wind chill: -19.7oC

Sunrise: 10.18am

Sunset: 3.35pm

 

 

The sun is getting closer to being visible at Scott Base.  It is actually above the horizon but still behind the hills and peaks of Ross Island.  There are some beautiful light effects and delicate colours to be seen in the sky.  Today there was a narrow, horizontal band of the palest pink in the South, across White and Black Islands, as the sun shone under the clouds in the North.

 

The sun getting closer! resized.jpg

The Sun Getting Closer!  John/AHT

 

While keeping a good look out for these beautiful effects, work and life at Scott Base must still go on.  Every Saturday at an All Staff Base Meeting, duties necessary for the smooth running of the Base are apportioned to all staff.

 

Base duties resized.jpg

Base Duties.  John/AHT

 

One such duty is the removal of snow and sea ice build up around Reverse Osmosis (RO) Intake/Outlet gantry at the ice transition.  Our team spent nearly two hours shovelling snow, cutting the sea ice with a chainsaw and removing these heavy blocks of ice.

 

The RO plant supplies all fresh water for the running of the base and provides two degrees of purity, RO1 for general use and a more pure RO2 for drinking, scientific projects, and work such as conservation of the Ross Island historic artefacts.

0

Ice and Snow Formations

Posted by Conservators Jun 3, 2011

Date: 02/06/2011

 

Posted by Julie

 

Temperature: -22

Wind Speed: Gusting between 20 – 40 knots
Temp with wind chill: - 36  to  -41
Sunrise: August
Sunset August

 

 

Ever since the spectacular ice breakout in February, the ice forming over the water in front of Scott Base has steadily been growing thicker.  Last week the ice was judged thick enough to walk on. Troy, our base leader, Jane, and I set out to mark a safe route for walking through some nearby pressure ridges.

 

Troy is an experienced glacier guide, and so we got the bonus of getting Troy to talk about the snow and ice.  In a crack in the ice we discovered some spectacular, large, faceted ice crystals.  This is sometimes known as crevasse hoar. Troy explained that these ice crystals form and grow in glacial crevasses and in other cavities where a large cooled space is formed and in which water vapor can accumulate under calm, still conditions with a large temperature gradient. The vapour then attaches itself straight to the ice crystal forming a hollow hexagonal shape.

 

faceted ice crystal.jpg

Faceted ice crystal. © AHT/Julie

We also found impressively large icicles.  Icicles require liquid water and so they are notable: the temperature rarely goes above freezing, and certainly has not been above 0 degrees for many months now.

 

Jane as a radioactive rhino.jpg

Jane impersonating a radioactive rhinoceros by shining her headlamp through an icicle. © AHT/Julie


Most spectacular are the pressure ridges themselves.  Pressure ridges form because even very thick sheets of sea ice are mobile. As the sea underneath moves, or when the temperatures fluctuate, the ice shrinks and expands, cracks and shifts.  At Scott Base, the sea ice is bordered by Ross Island on one side and the permanent, immobile ice shelf (80 km thick) on the other.  The relatively thin sea ice between has nowhere to move except upwards, and so plates of ice are very slowly pushed up vertically along cracks, eventually developing into spectacular ice formations. These pressure ridges survived the recent sea ice breakout in February, meaning they are at least 14 years old, the date of the last ice breakout.

 

Pressure ridges.jpg
Pressure ridges.  The formation in the foreground is approximately 5 meters high. © AHT/Julie