Sea Ice Report
November 17, 2003


	We have passed the mid-November point and the seasonal changes to the McMurdo Sound sea ice are mirroring past years. This updated sea ice report should bring light to these subtle changes and reiterate the need to travel cautiously for the remainder of the season. Credit is given to all the people that have supplied valuable information for this report:  Gerald Crist and Steve Zellerhoff with Fleet Ops; Jeff Scanniello, the McMurdo Station surveyor; and Keith Springer at Scott Base. Kelly Brunt, our talented mapping specialist has arrived to McMurdo Station and graciously produced one of her masterpieces for this sea ice report. 
	The overall sea ice conditions have completed the final stages of growth and have begun the transition to the warmer and less stable ice. Jeff Scanniello and myself have been checking temperature-gauging stations regularly and have concluded that the ice is now in period 2 conditions (14-23° F). The shift from period 1 (<14°F) to period 2 is relatively slow and gradual in comparison to the change from period 2 to period 3 (23-27°F). Last season we recorded the critical change from period 2 to period 3 in the second week of December. Most of the active or weak cracks that have been observed for the last two months have grown in thickness an average of three feet (90cm) The first year ice near the waters edge is now averaging about 75-80" thick (2m) with minimal snow cover.  Similarly the multi-year ice near the Dellbridge Islands and Cape Evans areas have thickened with averages about 90-95" (2.3-2.5m), but still has about two to three feet (80-100cm) of snow on top.
	The flagged routes that Field Safety Training monitors and reports on are well established and used by many. The main road to Cape Evans has been groomed once again by Fleets Ops due to the great amount of snow accumulation and the hazards this presents to non-tracked vehicles. It is still my recommendation that the Cape Evans recreational trips are safest with two or more Deltas. A new parking area for the recreation trips was established so that the Deltas did not have to drive over either of the wide cracks near Scott's Hut. It is recommended that all parties out there walk along the old road from the parking area over the two separate crack systems before turning toward the hut. Care should also be given to all of the tidal cracks because they become increasingly wider the closer to the hut you are. Additionally, there has been some concern with regards to sea ice travel off of established flagged routes and the safety protocols associated with such travel. USAP guidelines for sea ice travel are explicit with regard to properly checking out with Mac Ops on your planned route or final destination, carrying the appropriate survival gear for everyone traveling in the group and having a drilling device to use when crossing un-monitored cracks or pressure ridges. The gravitation to the open water is evident and should be approached with extreme caution, particularly in the ensuing weeks. Vehicles should remain a good distance from the ice edge, un-roped foot travel within twenty feet of the edge is strongly discouraged and all cracks and pressure ridges should be profiled before crossing.
	Closer to home, the ice pier in Winterquarters Bay is in its final stages of completion. The surface was repaired after last season's ship-offload by filling in the low spots with ice chips and flooding the surface with water and then leveling by a grater. Recently the cover layer of drifting snow was removed to expose the ice to the cold ambient air temperatures. To protect the pier surface from vehicle tracks and the suns radiant heat, Fleet Ops covered the ice with about eight inches (20cm) of crushed fines. Only the top layer of rocks will absorb the heat, leaving the remaining layers to insulate the lower ice surface. The last pier project to complete is the removal of the surrounding snowdrifts from the sea ice. This will serve two purposes: to subject the local sea ice to the solar heat and thus weaken the structural integrity, and to allow greater light in for the divers to see the pier's undersides.
Antarctica New Zealand is coming into full swing with a few science projects located around the Hut Point Peninsula. K057 is studying thermal sensitivity in the local fish just off of the Willy Transition area. K063 is working with the Weddell Seals north of Turtle Rock. K068 is finishing up their work off of Cape Armitage today and K082 finished their work out at Cape Evans recently.
If anyone out on the sea ice comes across newly formed cracks or finds some dramatic changes in the sea ice around your area of travel, please email me the info at the following address: brian.johnson@usap.gov. Thanks for the continued help in providing safe and useful sea ice information for the Ross Island area.
Until the next report, I wish you all safe travels on the sea ice.



Brian Johnson
Sea Ice Instructor