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!

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

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

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