Once having formed, these snow puddles usually continue to increase steadily in size during 

 the polar summer. Actually, in the case of chance freezes, the protective action of the ice rind 

 keeps the water from freezing. 



The following observations testify to the importance of the role of such a protective ice rind 

 in maintaining the high temperature of the water. 



During the expedition on the Sadko, on 30 August 1935, a water temperature of 0.25° was 

 observed in a water puddle on the light blue ice, the water being covered by an ice rind 10 cm thick. 

 The highest water temperature observed in the puddles under the protective rind was 1.2°. 



On 29 August 1939, according to observations of the Sedou a snow puddle was covered by a 

 surface layer of ice 4 cm thick, separated from the lower 7. 5 cm ice layer by a layer of very 

 watery flaked ice (kasha) 2 cm in thickness. Under this entire ice layer the water temperature was 

 0.2°. 



Inasmuch as the water temperature in the puddles on the ice gradually rises, and since the 

 water is constantly shifted by winds and other factors, with the passage of time the accumulation of 

 water in the ponds is caused not only by the melting of snow on the ice surface, but also on account 

 of the melting of the ice layers which are in direct contact with the water in the pond. 



At first, each individual water basin on the ice contains its own water and is isolated from the 

 neighboring ponds and from the sea underneath the ice. Actually, some of the snow water runs off 

 in the beginning into the cracks which are present in the sea ice. But upon meeting the ice layers 

 whose temperature at this time is still considerably under the freezing point, this water freezes, 

 stops up the cracks, and thus prevents the main body of water from running off under the ice. 



Thus the first melting of snow on the ice cover brings out the appearance of fresh water 

 basins on the ice, and these gradually increase in size and join one to another, so that by the end of 

 this process the surface of the melting ice, when seen from a distance, has the appearance of a sea 

 which is covered with small broken ice (figure 108). 



Rising over the water, whose depth reaches one meter and over in certain parts of the south- 

 em regions of the Arctic Basin, there may be seen only the tops of hummocks, stamukhi, and 

 chunks of many-year-old ice. * 



When the ice is thus covered with thaw water puddles its resemblance to the open sea is still 

 greater during a wind when the water surface is covered with ripples and small waves. 



This phenomenon is especially typical of the pripai (fast shore ice) along the arctic coast and 

 the islands, but it also takes place on the ice of the Arctic Basin. Thus, according to observations 

 of the Sedou on 20 July 1939, all the snow disappeared from the surface of the ice, and within the 

 range of visibility from the bridge it was possible to estimate that 40 per cent of the ice surface was 

 covered with snow puddles. 



*The Soviet in 1932 and the Krasin in 1935, in the Chukotsk Sea observed many-year-old 

 ice with height of 4 to 5 m over the water and depth of 10 to 12 m. The fresh water puddles on this 

 ice were as much as 6 m deep. On the ice field of the "North Pole" station, the dimensions of the 

 largest puddle were: length 400 m, width 200 m, depth 2. 4 m. 



301 



