No one knows if day 243 will turn out to be the annual minimum, but for now 2018 Arctic ice extent resembles a hockey stick. Presently the ice is 135k km2 below 2007 and the 11 year average (2007 to 2017 inclusive). MASIE shows increasing ice the first six days of September, while SII is hovering around 4.8 M km2, 200k km2 higher.
The image above shows ice extents on day 249 (September 6) for years since 2007. Note this year ice is strong in both East Siberian basin and in Canadian Archipelago. The exceptional 2012 low extent is also visible (Great Cyclone in August).
The Canadian ice chart below shows why the Northwest Passage is not passable this year. Brown indicates old ice, and green first year ice. In the last two days, Canadian Archipelago has added 38k km2 from its lowest extent on day 247.
The bottle neck even for small yachts is Franklin strait where even first year ice is not going away. Small vessels need less than 4/10 ice conditions indicated by the green spaces.
via Science Matters
September 7, 2018 at 10:30AM