The Loss of Decades Old Sea Ice Plugs in the Canadian Arctic Islands

Sverdrup Sound and Nansen Channel, along the northwestern coastline of the Queen Elizabeth Islands (QEI) in the Canadian High Arctic, have been blocked by sea ice plugs for several decades. These plugs constitute some of the oldest sea ice in the northern hemisphere and they block these northern channels from intrusions of sea ice from the Arctic Ocean. During the record minimum sea ice cover in the Queen Elizabeth Islands (QEI) in the summer of 1998, both these ice plugs were dislodged and removed from the Queen Elizabeth Islands. The last time this occurred was during another record minimum summer ice cover in 1962. Despite the exceptionally low sea-ice cover in 1998, reconstruction of a 38-year record of minimum sea ice extent from weekly Canadian sea ice charts shows no long term trend to less sea ice in the Queen Elizabeth Islands. Ice conditions for the summers of 1999 and 2000 suggest a return to normal ice conditions in the QEI and reformation of the ice plugs. The absence of any long term trend in sea ice extent and the recovery to normal sea ice conditions in 1999 and 2000 is consistent with large scale sea ice dynamics and atmospheric circulation which on average continuously forces the Arctic ice pack up against the northern coastline of the QEI. It is also consistent with differences in the trends in sea ice cover and length of the melt season between the eastern and western Arctic found in other studies.