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Northwest Passage Open 21 August 2008 |
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(3rd year in a row)
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National Ice Center, Washington, DC USA
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Last Update:
September 5, 2008
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Figure 1: [Top] Sea ice conditions from 21 August
2008 showing that the southern portion of the Northwest Passage (NWP)
is open and freely navigable [Source: Sea ice information from National
Ice Center; graphic created by Mr. Sherief Guirguis of U.S. Northern
Command.] The bottom graphics are presented to show historical conditions
from 2005 and 2007. [Left] Sea ice conditions from 29 August 2005,
with three possible shipping routes of the NWP indicated, compiled
using the National Ice Center bi-weekly ice charts. Both Victoria
Strait (southerly route) and Parry Channel (northerly routes) were
blocked by sea ice. [Center] Sea ice conditions from 31 August 2007.
The southerly route or the NWP via Victoria Strait was mostly ice-free,
but Queen Maud Gulf contained areas of <1/10 ice (dark green),
indicating hazards still existed. However, Amundsen’s route
through the NWP was ice-free. [Right] Sea ice conditions from 14
September 2007. Parry Channel continued to have ice hazards, and
some ice was present at the eastern entrance to Lancaster Sound.
While large segments of the southerly route of the NWP remained freely
navigable, the NWP was not completely ice-free. [Source: National
Ice Center bi-weekly ice charts.] |
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21 August 2008 - The National Ice Center, with
collaboration and input from the Canadian Ice Service of Environment
Canada, has
determined
that the Southern route of the Northwest Passage (via Peel Sound,
Franklin, Victoria Strait and then west through Queen Maud Gulf,
Coronation Gulf, and Amundsen Gulf) is now open, meaning there is
now a freely navigable route between Baffin Bay and the Beaufort
Sea. The World Meteorological Organization (WMO) defines “open” as less than 1/10 sea ice concentration with no ice of land origin (landfast ice or icebergs). The term “freely navigable” is equivalent. The sea ice charts produced by the analysts at the National Ice Center (Suitland, MD) and the Canadian Ice Service (Ottawa, ON) follow the WMO convention for ice concentration and stage of development. The National Ice Center defines “ice-free” only where its analysts determine there is no ice of any origin present. The conditions leading to the opening of the Passage depend in part to the transport of ice from the Arctic Ocean south through the Canadian Archipelago. As ice melts in the south, it is replaced by ice drifting from the north, which collects in “choke points” such as Victoria Strait. In a normal year multiyear ice floes filter south. During the record sea ice minimum extent in 2007, the existing multiyear ice north of Parry Channel melted. Hence, in 2008, much more of the ice carried southward was first-year ice, which is thinner and more prone to melt. July mean surface air temperatures were 2.5° C higher than average over the region, and a strong high pressure system centered to the north encouraged drift-out and melt-out of the ice in Amundsen and Coronation Gulfs. August air temperatures continue to be above average, locally up to 4° C higher over M’Clintock Channel and Victoria Strait. While the Southern route is open, the Northern route (via Viscount Melville Sound and M’Clure Strait), remains ice-covered. |
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Figure 2: Surface Air Temperature anomaly, degrees
C, for the Canadian Arctic Archipelago, August 1-19, 2008 (courtesy
NOAA Earth Systems Research Laboratory)
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Declaring the NWP to be “open” indicates
the presence of a continuous freely navigable path from west to east.
In reality, a ship or convoy might take days, weeks, or months to
traverse the route, and conditions would undoubtedly change during
the voyage due to drifting ice and changing weather. Icebergs and
multiyear ice floes, even small ones, still are significant navigational
hazards, and even ships with experienced crews may experience difficulty.
The Arctic continues to be a harsh environment where conditions may
change rapidly, including the conditions within the NWP. The National Ice Center is a unique national asset and a successful model of a Joint Interagency Command consisting of U.S. Navy, National Oceanic and Atmospheric Administration (NOAA) and U.S. Coast Guard personnel. The NIC’s mission is to provide global, regional and tactical scale sea ice analyses and forecasts serving national interests and is regarded the as the foremost U.S. agency in polar ice prediction. The National Ice Center is a member of the North American Ice Service, comprised of the National Ice Center, the Canadian Ice Service of Environment Canada, and the U.S. Coast Guard International Ice Patrol. |
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For more information, please contact: |
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To view previous Press Releases,
please click on this link: Previous Press Releases.
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