It has been a sobering week. At the time we were initially caught by the sea ice, the Shokalskiy was just 2 to 4 nautical miles from open water. Now the sea ice distance has become even greater with the continued winds from the east, putting our nearest point of exit at some 16 nautical miles. The international effort has been extraordinary and we are incredibly grateful for all the hard work and effort everyone has provided to assist the Australasian Antarctic Expedition 2013-14 in escaping from the ice – a big thanks in particular to the Chinese, French and Australians, co-ordinated by the Australian Maritime Rescue Centre. The winds have eased slightly but at times have reached in excess of 70 kilometres an hour – equivalent to the average conditions experienced by Sir Douglas Mawson’s original expedition a century ago at Cape Denison. It is humbling to consider these men not only survived but thrived, mounting a major scientific expedition. A continent of extremes was revealed and communicated by the latest radio technology to the public at home.
The conditions we are experiencing over the Shokalskiy are a result of the frequent and deep low pressure systems that encircle the continent. In combination with a funnelling effect from the ice sheet, these lows are producing strong and pervasive winds from the southeast. The wind is not unusual but what is unexpected is the major reconfiguration of thick multi-year sea ice to the east of the Mertz Glacier. In 2010, a large iceberg known as B09B, calved from the continent and collided spectacularly with the extended tongue of the Mertz Glacier. The knock-on effect has been that Commonwealth Bay has filled with sea ice (termed ‘fast ice’), preventing direct access from the sea to Mawson’s main hut at Cape Denison. Unfortunately for the AAE, it appears the region has just undergone a massive reconfiguration of sea ice, years after the loss of the Mertz Glacier tongue. This has been revealed by new satellite imagery which arrived today from the AAD/ACE CRC Sea Ice Group in Hobart, Tasmania. The satellite maps show the comparison before and after the event, with deep purple signifying 100% sea ice cover and dark blue, open water. (Note: the outline of the Mertz Glacier tongue is shown on the maps but disappeared following the collision with B09B). Crucially, these images show the extensive, thick multi-year sea ice along the eastern and southern edge of what was the Mertz Glacier Tongue (outlined by a red box) has been blown out in the last week and driven against our position by the persistent southeasterly winds. It is too early to identify the cause of this remobilisation of ice but we may be looking at the future long-term expansion of fast ice to the east of Commonwealth Bay.
The thick chaotic surface we see around the Shokalskiy is consistent with the idea that this ice is several years old and is considerably more difficult to break through by icebreaker than single year ice. The presence of dark watersky to the southeast shows the presence of open water which is reflecting off the underneath of clouds. We hope the Australian ice breaker Aurora australis may have more luck finding leads from this ice edge to reach the Shokalskiy. We are all hoping the Shokalskiy will find a route out thanks to the efforts of the Australian and Chinese icebreakers.
Meanwhile on board the Shokalskiy, moral remains good and the team are pulling together in an extraordinary way. Everyone is working hard to support one another. Take a look at the video diaries on the Intrepid Science YouTube Channel to see what we are up to. We are all keeping busy, with twice daily briefings outlining all the information we have to hand, alongside classes through the day (knot tying, languages, yoga, photography and many others) while the science programme has continued as best we can.
Thanks for all your support and we hope to see you all soon.
(Editor’s note: this post was originally published on the 30/12/13 – the published date has been changed to keep it on the home page temporarily)