Auroras and emperor penguins are featured and Mawson’s station leader provide’s a comprehensive description of sea ice.

Antarctic photography

One of the great aspects of being in Antarctica is the opportunity for photography.

The variety of unique wildlife provides an almost endless array of subjects which can be captured by the amateur photographer. Now that digital cameras are the preferred medium, first timers just take a lot of photos hoping for that one great shot. I know several expeditioners who finish a year with 10,000 plus photos. It does lead to a big editing job but having experienced two previous winters, I can attest you actually enjoy reviewing the photos and reliving the time in Antarctica.

Of course wildlife is just one subject, and auroras are another favourite down south. Many a night is spent outside with a tripod hoping for that one shot that will capture the majestic beauty of an Antarctic night sky in full auroral bloom. Several also attempt time lapse photography with varying results. The main problem is battery life at −20°C.

Then there are the sunsets, landscapes, icebergs and the people. It’s the people that make an Antarctic experience, so some ‘happy snaps’ of them are always in order.

Andy Burgess

Sea ice 101

Whilst ‘The Mawsonites’ trek out and across the sea ice I appreciate our wives, girlfriends, and Mums sitting at home and stressing, wondering if their loved ones are safe. So, I thought it timely we have a wee lesson on sea ice. It is the intent of this article to alleviate at least a bit of the anxiety some of you may experience when your adventure hungry, risk seeking, fun loving husband, wife, mate or other treks out onto the sea ice and travels vast distances in search of that ultimate photograph of emperor penguins 55 kilometres away at Auster rookery or further still to Colbeck Hut (95 kilometres from station).

Yes there is risk, of course, but I can assure you that we take every precaution to mitigate those risks and have trained, and honed our skills well before venturing onto the sea ice for the first time.

So here goes… ‘Sea ice 101'.

What is sea ice?

Sea ice is merely a frozen film on the surface of the ocean. That should make you feel more at ease? It is of uncertain and unpredictable thickness, strength, reliability and permanence. How about now? And people can get injured whilst travelling on the sea ice. Ok enough.

This is information is lifted from the Australian Antarctic Division field manual which is the ‘go to’ manual for all expeditioners. We all have one and we carry it with us whenever we are out in the field. This is also the message our field training officer (FTO), Heidi, gives to each of us during our training. We do not take travel on the sea ice for granted.

Sea ice starts forming once the water temperature has dropped below −2°C and the most extensive growth occurs between March and May where newly forming sea ice can grow as much as five centimetres every day. The ice forms at the surface and grows its way down, and over the winter the sea ice grows to thicknesses in excess of one metre. In fact, the fast ice — I’II explain fast ice in a moment — can grow as thick as two metres. This is because it is near the coastline where the conditions are calmer. The sea ice in Horseshoe Harbour (just out the front of the station) is currently 1.6 metres thick and growing.

Sea ice formation?

We have various ways to describe the sea ice as it progresses from ice crystals through to the stuff we walk, ski and drive on. There is frazil — ice crystals forming on the surface; grease (or plastic ice) — newly forming sea ice and resembles an oil slick or grease on the surface of the ocean; and pancake ice — again newly forming sea ice where patches (pancakes) of ice are beginning to bond together as they seek one another out so as to join and grow together. You will find photographs of each of these below.

Earlier in this story I referred to fast ice. Sea ice forms in many different ways and thus has numerous definitions. There is fast ice — sea ice that is attached to the coast (a bit of an oxymoron as it really isn’t going anywhere fast at all!). The name refers to it being locked FAST to the land. ‘Lead’ is a long open break in the sea ice that may continue to open and close with the tides and can be many kilometres long. Tide cracks are are cracks in the sea ice that have formed as a result of the fast ice separating from the coast, an island or an iceberg. And finally there is a polynya — these are open bodies of water (like a lake) contained within the sea ice. They have not frozen over and are kept ice free by the wind and ocean currents.

How much sea ice is there?

As stated earlier, the sea ice starts to grow in the autumn and continues to grow over the winter. By the time spring is upon us the extent of the sea ice has reached its maximum, approximately 20 million square kilometres in total. The sea ice begins to decay in spring. For us at Mawson, this decaying process will start in mid to late October. The sea ice eventually breaks up and melts over the summer where the total extent of sea ice in Antarctica reduces to three million square kilometres.

What about hazards?

Yes there are hazards. The sea ice can breakout at anytime and in some areas of Antarctica a small ocean swell of one centimetre coupled with a strong offshore wind is enough to cause the sea ice to break out. Whilst this is extremely rare in the Mawson area, we never camp on the sea ice.

Tide cracks and leads are the most common hazard we encounter on our traverses across the sea ice. Tide cracks form close to shore where floating ice (remembering all ice is floating on top of the ocean) meets the ice foot frozen to the land (refer diagram below). Leads are long open cracks or channels that can gradually spread. Often the open water in the crack of a lead will re-freeze but this new ice is thin and may be of poor quality. This poses a risk when attempting to cross in a Hägglunds. Expeditioners are well versed at assessing and profiling the sea ice and take great care to drill the sea ice to gauge its depth, strength and cross-ability (refer attached diagram). Each Hägglunds is equipped with a battery powered and a hand ‘expeditioner’ powered drill. These are known as ice augers. Also contained in the sea ice drilling kit is a tape measure. This is used to lower into the drilled hole so as to measure the thickness of the sea ice.

When drilling the sea ice expeditioners are not only concerned with the depth of the sea ice but also the quality of the ice shavings that emerge from the hole. Light, dry ice shavings indicate good quality and compact sea ice whilst wet, slushy shavings can be an indication of decaying sea ice.

Then there is thin ice. The sea ice is thinner wherever ocean currents are faster. This occurs in narrows between islands, at headlands, over reefs, shoals and shallow water. Thin ice is depicted by its dark grey colour.

Weather and travel

Before travelling on the sea ice expeditioners make themselves aware of the weather. Some of the weather considerations when travelling on the sea ice include:

  • wind speed
  • air temperature
  • visibility
  • surface definition

Before travelling on the sea ice, expeditioners will speak to the station leader and make their intentions known. If they are intending to camp overnight they complete a trip intentions form and submit this to the station leader at least three days in advance. They clearly identify their intentions to the station leader and all parties discuss and assess the risks including identifying escape routes should there be a need to get off the sea ice. When deciding on a route, expeditioners rely on those that have gone before them for information about the route, again identifying hazards and risks. All routes are recorded and saved on the computer mapping software and this information is passed on from one year to the next.

Whilst on the sea ice, expeditioners carry an extensive amount of equipment both on their person, and on the quad motorcycle or in the Hägglunds. There is too much equipment to list here but in short this ranges from an ice axe and throw bag to survival packs containing tents, spare clothes and sleeping bags to many days’ rations of food. The vehicles are also equipped with sea ice recovery kits including winches and cables, and even ramps to place across tide cracks and leads.


Finally you may take some comfort in the fact that the Australian Antarctic Division (AAD) has been doing this for many years and expeditioners have honed and developed their skills, knowledge and understanding of the sea ice across decades, passing this knowledge onto the next generation of expeditioners.

Through this, the AAD has developed strict guidelines that determine when expeditioners can travel on the sea ice and in particular, the required thickness of the ice. The sea ice is opened for travel every year on 16 May through to 25 November. The station leader must monitor measure and record the depth of the sea ice leading up to this time and report these to the operations manager at headquarters in Kingston, Tasmania for final approval before sea ice travel can commence. The station leader usually relies on the FTO and other experienced expeditioners to do this. Then the FTO will provide sea ice training to each expeditioner before the operations manager and station leader approve sea ice travel.

The thicknesses are as follows:

  • 20cm: person on foot/skis
  • 40cm: quad motorcycle/skidoo
  • 60cm: Hägglunds

So there you have it. A quick lesson on sea ice. I do hope this article will help ease the anxiety and stress experienced by some. Remember, we have been doing this for a long time and I assure you that I want your loved ones to return home to you — probably a whole lot more than you do?

Steve Robertson, Station Leader