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Antarctic conservation

2 Posts tagged with the cracks tag
1

Cracks in the ice

Posted by Conservators Sep 28, 2012

Author: Martin

Date: 25 September 2012

Temperature: -28C

Wind Speed: 20 knots

Temp with wind chill: -45C

Sunrise: 6:06am

Sunset: 7:27pm

 

 

After many days of storms, blowing snow and very little visibility we were finally ready to leave Scott Base and to go out again on a stunningly beautiful day. No wind, clear sky, sun and spectacular views of the Trans Antarctic Mountains – we couldn’t ask for more and were keen to get to the historic hut at Cape Evans. 

 

Travelling to Robert Falcon Scott’s Terra Nova Hut, which he built as an expedition base for his British Antarctic Expedition (1910–1913), involves driving  over sea ice for approx. 20 km. 

Jana ice.jpg

Jana helping to drill holes into the ice sheet © AHT/Martin

 

Even though the ice thickness is sufficient by now, there are still some cracks which need to be profiled. It means drilling several holes in to the ice right through to the water and measuring the thickness of the ice sheet. A tape measure and string attached to a weight which hooks itself to the underside of the ice sheet is very simple but works well. With a little tug on the string the weight is released again. By measuring several holes across the crack, the shape and therefore the stability of the ice around it, can be determined. It is a time consuming task, especially if you have to do it several times on a trip, but the alternative of breaking through the ice with your vehicle is a lot less attractive.    

 

crack.jpg

Cracks in an iceberg © AHT/Martin

0

Sea Ice Formation

Posted by Conservators Oct 4, 2011

Author: Jane
Date: 30 September 2011
Temperature: -26°C
Wind Speed: 12 knots
Temp with wind chill: -40°C

 


This has been an unusual year for the sea ice around Scott Base. In March it broke out in front of the base for the first time since 1997. The sea ice began to form again soon after the ice floes were washed out of McMurdo Sound. It is now around 1.8m thick in front of the base.

 

Image 1.jpg

The ‘Big John’ crack extending out from Hut Point into McMurdo sound. This crack is now impassable. Mount Discovery to the right and Black Island to the left, with a mirage visible along the bottom.  Photo AHT/ Jane

 

 

Further North the sea ice is still moving, causing the formation of large cracks. We managed to get to Cape Evans to do our Winter Hut Inspection on September 17th, but we had to park the Hagglund a few hundred metres out from the shore due to cracks in the sea ice which were not safe to cross in a vehicle. A few days later it was impossible to get to this area, as cracks along the flagged route had opened up substantially. One of the cracks we crossed is now about 2.5m wide.

 

Image 2.jpg

Looking down on Terra Nova hut from Windvane Hill with the Barne Glacier in the background and the Hagglund parked out on the Sea Ice.
Photo AHT/ Jane

The edge of the sea ice is now close to Cape Royds which is much further South than it has been in recent years. It has been very warm this winter, with temperatures often in the range of  -10°C to -20°C.  This combined with the frequent stormy conditions has hindered the sea ice formation. The cut-off date for sea ice growth is usually mid-October so it is unlikely to improve enough to allow for vehicle travel in the area over the summer season. This will have an impact on our work.


To see out what our weather looks like on Ross Island you can check out the webcams at Scott Base, Arrival Heights and the windfarm by clicking on this link: http://www.antarcticanz.govt.nz/scott-base/webcams