114 POLAR PROBLEMS 



j light — up to 2 feet in thickness 

 Strength i heavy — more than 2 feet in thickness 



[ rafted^^ (telescoped; Russian, nahivnoi) 



level (flat) 

 hummocky 

 moutonnee^^ ■ 

 honeycombed 



Surface i 



close — when they touch each other for the most part 

 Arrangement^^ i open — when they do not touch each other for the 

 I most part 



The third class of ice covering the Arctic Sea, the Arctic Pack, 

 consists of the same main types of sea ice which are inherent in the 

 pack ice, i. e. fields, floes, hummocks, but they are of much larger 

 dimensions and power, while the products of the further breaking 

 up and disintegration of the sea ice, namely the types glagons and 

 growlers, are of insignificant importance in the Arctic Pack, being 

 alternately formed and disintegrated in the temporary polynyas, 

 lanes, or cracks, where also takes place the formation of the primary 

 types of sea ice, slush or sludge, and pancake ice. 



Sea Ice Definitions 



We shall now summarize in the form of specific definitions what 

 has gone before. 



Slush, or sludge. The initial state in the freezing of sea water when 

 it is of the consistency of gruel or soup and the surface of the 

 water takes on the appearance of cooling grease with a peculiar 

 steel-gray or lead tint. 



Pancake ice. Small cakes of new ice approximately circular and 

 with raised rims. Diameter of cakes is from i to 2 or 3 feet; 

 their thickness up to 2 to 4 centimeters ; rims are i to 2 centi- 

 meters high. 



Young ice. Compact ice sheet formed from the repeated freezing 

 together and breaking up of pieces of pancake ice. Its initial 

 thickness is 2 to 4 centimeters, which increases during the 

 winter to about 2 meters and as a maximum 3 meters. 



" The thickness of rafted floes in the Kara and Siberian Seas is from 3 to 10 meters, and near 

 the limits of the Arctic Pack, with the participation of floes of the latter added, it reaches 20 to 25 

 and even 30 meters. 



1- By analogy with roche moutonnee, the weathering of the ice producing rounded surface forms 

 (see Fig. 16) similar to those produced by ice action on rock. 



1^ As to navigability these two forms may be characterized as follows: 

 close pack — when it is not possible to navigate through it. 



open pack — when it is possible to navigate through it but changes in the vessel's course are 

 continually necessary. 

 Certainly, when the pack ice is composed of gla(ons, the possibility to navigate through it is greater. 



