Over the last few years the northern hemisphere has seen huge variations in winter temperatures. This is caused by a weather pattern called the Arctic oscillation. It has a negative and a positive phase shifting from year to year and month to month. The Negative phase brings low pressures to the Arctic region and the frigid Arctic winds are pushed into Europe and North America. We are particularly interested in this weather phenomenon as it also controls the ice conditions of 
our route. In its positive phase multiyear ice flows from Siberia towards Greenland and North America and is pushed out of the Arctic through the Fram Strait between Greenland and Svalbard. This means less ice in the arctic and thinner summer ice but it’s also means that multiyear ice is pushed into the narrow channels and straights of the Canadian Arctic and might block our route. In June the annual Sea Ice Outlook Report is released by the NOAA and we are excited to see what we can expect. The Arctic oscillation is just one of a large number of known and unknown factors that control the ice extent and in the end no man or computer can predict how the ice will behave from year to year.
I found this beautiful NASA animation that shows the movements of the ice during 2010 which had the third lowest ice extent ever recorded. At 0:30 into the video you can see how the Ice is retracting from the Northwest Passage during a short period of time and that our northern passage never fully opens up.
