During our travels along the Labrador coast during the early part of the 2008 summer ice and icebergs became a daily part of our life. As we travel further into to Arctic we will encounter a lot of floating ice, there will be many icebergs in Baffin Bay, but as we progress it will be sea ice that will be the determining factor effecting our success progress. Following is some explanation of floating ice.
Floating ice can be divided into two main categories: sea ice and icebergs.
Sea ice is defined as “any ice that is found at sea that has originated from the freezing of sea water”.
Icebergs are defined as “a massive piece of ice of greatly varying shape, protruding more than 5m above sea level, which has broken away from a glacier, and which may be afloat or aground. Icebergs may be described as tabular, domeshaped, sloping, pinnacled, weathered or glacier bergs”.
Although icebergs will be numerous north of St John and are a danger to commercial shipping further south, they can be easily navigated when detected. On board Tyhina this will involve the use of radar and most importantly keeping a good watch. Smaller growler icebergs may go undetected by radar so it is essential that the crew are vigilant at all times, should Tyhina run into even a small one of these she would come off second best.
For a small yacht sea ice is the biggest impediment to navigation and its safety. Unlike ice breaking ships which can navigate through thick ice, Tyhina will only be able to navigate via open leads between the pack. The coverage of seq ice is described in tenths of sea surface covered. In talking to other sailors that have navigated through the Arctic, 5/10ths will most likely be the limit through which we can effectively navigate.
Although 5/10ths sounds like it would be comfortable going with only half of the sea surface covered, what often happens is that more closely packed bands form where there are no gaps at all. A band of ice like this of one or two hundred metres in width is as good as one or two kilometres and is unlikely to be breached by a small yacht.
Sea ice conditions can change quickly, what was open water one day can be congested with 9/10ths ice 24 hours later and similarly what was impassable one day may be relatively clear going the next.
Thus patience, persistence, opportunism and luck seem to be what is needed to get through the Northwest Passage in a small boat.
The relative pack ice conditions are shown below:
40000 icebergs are calved into Davis Strait and Baffin Bay by the glaciers of west Greenland every year. These take on many different shapes and sizes and like sea ice have a classification regime. Glacier ice is much harder than sea ice and so run ins with icebergs are to be avoided. An iceberg's movement is influenced by current, as opposed to sea ice which can be greatly affected by wind. Below are some iceberg classification photos and explanations.
