January. On the return trip, open water was traversed south of 70°30'S 

 to McMurdo, where ice was re-entered. 



From 12 through 15 March i960, ATKA proceeded to McMurdo Sound and 

 then north via Hallett Station, west of the 173 *E meridian (Pig. 21 ). 

 Ice was encountered all along the ship's track to Cape Adare, except 

 around Coulman Island. New ice was rapidly forming. From McMurdo to 

 Coulman Island, this new ice was young slush, varying from three- to 

 eight tenths concentration and averaging one-foot thick. In contrast to 

 this, along the coast from Cape Hallett to Cape Adare, the ice was pri- 

 marily rotten winter ice, two- and three-foot thick block and brash, 

 with young ice secondary. Six- to eight-tenths concentration was re- 

 corded. After departing the ice north of Cape Adare, no ice was 

 encountered. 



EASTWIND first entered ice at approximately 68 "S, 179*E> on 13 

 January i960, while in transit from New Zealand to McMurdo Sound (Fig. 22). 

 From this position to 73°30'S, the concentration varied from one- to nine- 

 tenths of brash, block, and small and medium floes of two- to four-foot 

 thickness. No ice was observed from 73*30'S to the vicinity of Beaufort 

 Island, where nine-tenths coverage was encountered. 



In McMurdo Sound, small, medium, and large floes of five-foot thick- 

 ness were concentrated along the western shore and to the north of 

 Marble Point. Fast bay ice extended as far north as Tent Island. 



On 2 February, the ship departed McMurdo for Hallett Station. Little 

 ice was encountered before arriving in the vicinity of Moubray Bay, where 

 five- to seven-tenths concentration was entered. Hallett Harbor was ice 

 free except for a few grounded bergs on 3 February. During three days at 

 Hallett, up to five- tenths concentration of ice moved in and out of the 

 harbor daily with the changes of tide. On 6 February, EASTWIND departed 

 Hallett Station for McMurdo escorting ARNEB. Their route was to the west 

 of Coulman Island through five- to seven-tenths of brash, block, and small 

 floes, averaging four-foot thick. Open water extended from just south of 

 Coulman Island to McMurdo Sound. 



EASTWTND departed McMurdo 27 February for Sidney, Australia, via 

 Hallett Station. At the time of departure, the fast bay ice extended 

 about two miles north of NAF McMurdo, from the Glacier Tongue to the 

 Dailey Islands. After leaving McMurdo Sound area, the only ice 

 encountered was in the vicinity of Cape Hallett where the same ice 

 conditions existed as reported above. 



2. Amundsen - Bellingshausen Seas Area 



While proceeding southward to rendezvous with GLACIER for 

 scientific survey operations at the Thurston Peninsula area, BURTON 

 ISLAND first sighted ice on 12 February at 67*30'S, 92«W (Fig. 23). 



kk 



