THE GEOGRAPHICAL FEATURES OF THE ROSS SEA AREA. 3 



over with ice which in the course of the winter attains a thickness of between ten and 

 fifteen feet. Also along the western coast all the bays and inlets are frozen and the fixed 

 ice probably extends several miles out from the coast. Between the fixed ice on the two 

 sides there is an area which is sometimes frozen over and sometimes free from ice, even in 

 the middle of the winter. That .such a region of thin variable ice does exist was made 

 certain by the observations of the party which visited Cape. Crozier in July 1911. From 

 Cape Crozier the Ross Sea can be seen, and the party made a record of the changes in 

 the ice-covering of the sea during the time they spent there. 



When they arrived on the 15th July they found that the Ross Sea was completely 

 frozen as far north as they could see, ' but much of the ice appeared to be young and 

 thin, with little snow en it.' The next day they saw in the distance a cloud of frost 

 smoke, which is a sure sign of open water. On the 17th they report ' two open leads of 

 water, like broad irregular streets extending from the Cape Crozier cliffs away to the north- 

 east and lying more or less parallel to one another.' These leads had disappeared the 

 next day, but more open water was seen on the 19th. When this party descended to the 

 sea ice they came to the conclusion that the ice had shortly before been blown out and 

 only recently formed again, and they note ' some support is lent to this po.ssibility by the 

 absence of all snow-drifts on to the sea ice from the ice foot.' 



A day or two after the party reached Cape Crozier a very severe gale occurred. 

 For several days winds of hurricane force blew. When the wind dropped and the Ross 

 Sea could again be seen it was found that the ice had all been blown north. Cherry-Garrard 

 says ' in the gale the ice went right out from the Barrier as far as we could see. But 

 we could see the ice on the liorizon from 900 feet up : just a line of blink, but it was 

 there I feel sure. Otherwise open sea.' 



Everything therefore points to the centre of the Ross Sea being a region in which the 

 ice is constantly forming and being blown away so that it can never become thick, and in 

 which open water is constantly present either in leads or large open expanses. 



Very little is known about the winter ice conditions in the north of the Ross Sea, 

 The only information is that obtained from observations made at Cape Adare. At Cape 

 Adare the station was on the west of a lofty promontory and only the sea to the north- 

 west was visible from the station. Young ice commenced to form during the first week 

 of April, but here again it was constantly removed by high winds. It was not until the 

 end of May that the ice was sufficiently firm to allow of journeys being made across it. 

 After this large leads were opened by every gale and the presence of Antarctic petrols in 

 July indicated that the open water was not very far away to the north. At the end of 

 October the sea ice became too rotten for safe sledge travelling and in December the ice 

 both cast and west of the Cape broke out with great rapidity. 



These observations point to the ice conditions at the north of the Ross Sea being very 

 similar to those seen from Cape Crozier, and probably the ice here never becomes more than 

 four or five feet thick, and is constantly, during the whole winter, opening up to produce 

 long and wide leads of open water. These conditions probably exist to two or three hundred 

 miles to the north of Cape Adare, whore the northern boundary of the frozen area is very 

 hkely composed of pack sometimes free and sometimes fu'mly bound together by thin new- 

 ice. 



The ice conditions in the Ross Sea are therefore in the main something as follows : — 

 In the summer the open water is bounded on the west by the coast of South Victoria Land, 

 on the south by the vertical face of the Great Ice Barrier, and on the east by a variable 



