Figure 92. An ice hummock from complete breakup. 



Let us further assume that the wind begins with a sufficient force. Gradually the ice fields, 

 beginning with the windward side, will begin to move. Large ice fields, pressing on fields which 

 are leeward before starting into motion, crumple and heap the young ice, which had been formed 

 between them during the time of the calm. In such a way, the movement is gradually transferred 

 to new powerful ice hills which in turn will crumple the young ice which is located between them 

 and the succeeding powerful ice fields. It is clear that with the collisions of large powerful ice 

 fields not only young ice between them is crumpled but also their own borders of contact. 



If viewed from above, it would be possible to see how an interrupted strip of ice heaping runs 

 leeward zigzag from one field to another. 



With a very sharp increase of the wind force not only the young ice but also weak ice fields 

 are heaped. In such a case, it was as if an ice surge had passed along the ice fields which was 

 reminiscent of a breaker rolling into the shallows and breaking with spray and foam. After the 

 ice surge, the ice field which was level until then represents a chaos of raised heaps of diverse 

 forms and sizes. It seems that the vigorous ice fields of the Central Arctic Basin are created 

 chiefly after such ice heapings and after vatious processes level out their upper and lower 

 surfaces . 



The top ice hummocks, although their height over the level ice is less, also represents quite 

 vigorous ones. With their formation, the ice fields very often, even without any fracture, as it 

 were, push one under the other. The observations of the Sedov at the time of its drift, give the 

 idea of the process of rafting ice fields. 



On 2 and 3 January 1938 in the drift region of the Sedou, the ice fields were rafted over one 

 another in widths of 30 to 40 meters. The Sedou was at the same time exactly on the lines of 

 movement. At 1600 3 January, impacts of ice were heard against the bottom of the ship; selvage 

 of the neighboring field reached the ship and crossed under it. For 2 to 3 minutes, the impacts in 

 the ice began to reboimd even on the other side of the ship. The ice cover at this place was 



262 



