McMurdo Sound Sea Ice Report Dec. 2008

"McMurdo Sound Sea Ice Report
17 December 2008

Greetings from Ross Island!

All major science projects on the McMurdo area sea ice have concluded for the season. All fish huts and camp equipment have been retrieved off the sea ice. Deflagging of sea ice routes north of Hut Point will begin later this week. Therefore, effective 18 December all sea ice routes north of Hut Point are closed to USAP participants. Groups requiring access to closed sea ice areas should contact FSTP at x2345 for current conditions and approval. Other sea ice routes, including the Cape Armitage route, will remain open as long as conditions permit. Wheeled vehicle roadways are not affected by this closure.

This will be the final sea ice report of the 08/09 season. Over the last two weeks the McMurdo area sea ice has warmed and become more active. Average ice thickness has changed little, however the ice is softer and weaker, with larger melt pools and more cracks appearing. Average sea ice temperature measures -4.6 Celsius putting the ice in Period 3. Multi-year ice thicknesses range from 2.8m to over 5m while first year ice averages 1.2-1.6m. Heading north towards Cape Royds, you can expect slight warming and thinning of the ice along with active crack crossings requiring bridging timbers. Tis the season for sea ice closures. Numerous surface melt pools, general thinning, increased cracking and seal activity, as well as flooding around pressure ridges continues. Travelers should stay off of sea ice routes north of Hut Point and continue viewing sea ice features with suspicion, exercising particular caution while on foot. Continued warming and thinning will result in the closure of remaining McMurdo sea ice routes within the next few weeks. Please do not venture onto the sea ice surrounding Hut Point and the ice pier. Open water abounds and the melt pools here are particularly deep. Please observe the seals from a distance.

The most recent MODIS imagery http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=RossSea.2008346.terra.250m shows the ice edge running from Cape Crozier to the middle of Beaufort Island and extending in a “C” shape to the north towards the Drygalski Ice Tongue. This still puts the ice edge about 60 miles north of McMurdo.
Waypoints and local route files for your GPS are available from FSTP."

-Nick Giguere, Sea Ice POC