PACK-ICE 301 



Pack-ice. — The ice conditions in the Ross Sea have been 

 observed in the course of five different seasons. Although 

 differences in date make it impossible to compare these seasons 

 closely, one is led to believe that four were very similar and 

 constitute the normal condition, whilst one — the summer of 

 1902-3 — was exceptional. The normal condition seems to be 

 that the sea becomes completely frozen over in the winter, the 

 movement of the ice-sheet leaving narrow spaces of open water 

 only at its edge, in such places as the northern face of the Great 

 Barrier, and possibly in rents which are speedily refrozen. 



The gales at Cape Crozier grow excessively violent towards 

 the end of September and in October, and by this time the 

 ice-sheet has probably commenced to weaken. The general 

 break-up which results was witnessed on two occasions by our 

 sledge parties ; on one day they saw the sea completely covered 

 with ice, and on the next looked forth on a clear sheet of open 

 water. The ice thus freed drifts to the north, and forms that 

 belt of pack through which ships must pass to reach the sea in 

 the early summer. Drifting under the influence of wind, loose 

 pieces will always travel faster than the main pack, and con- 

 sequently the southern edge of the belt will generally be a hard 

 and fast line where loose pieces are crowding on the main pack, 

 and the northern edge will be free where loose pieces are 

 tending to detach themselves from it. 



Towards the end of December and the early part of January 

 this belt extends from the Antarctic Circle for about 200 miles 

 to the south, and is probably best attacked on the meridians of 

 178 to i3o° E. To the westward of this the pack would be 

 augmented by the /coastal ice of Victoria Land, and to the 

 eastward by conditions which are not well known, but on which 

 the discovery of Scott Island and the difficulties experienced 

 by Ross throw some light. 



The ice probably leaves the Ross Sea in large fields and is 

 broken by the ocean swell, which penetrates the pack for a 

 great distance; and this accounts for the fact that the floes 

 increase in size as one approaches the southern edge, though 

 nowhere exceeding one or two miles in length, The character 



