402 Alf, Trolle. 



When the openings had become sufficiently large, and the fjord- 

 ice further was loosened along land, it broke up into large floes, which 

 were gradually broken into smaller and smaller pieces. In a similar 

 manner the sea-ice broke up during an offshore wind, after a high 

 tide had loosened it from rocks and skerries. 



Observations on the ice conditions in the Greenland Sea 



and in the fjords and sounds at ca. 76° N. L. in North-East 



Greenland 1906—1908. 



The ice conditions in the Greenland Sea during the summers 

 of 1906 — 08 have been mentioned under the description of the 

 voyage. 



In both summers the drift-ice lay in the main in three zones, 

 namely, from east to west: 



(1) the outer zone with comparatively scattered pack-ice, which 

 was met with out over the Greenland Sea and in over the steep slope 

 of the Continental Shelf. 



(2) the central zone, with the main mass of polar pack-ice in over 

 the Greenland Shelf from its eastern, steeply descending margin 

 towards the west as far as an imaginary line connecting approximately 

 Greenland N. E. Runding to Shannon Isl., 



(3) the inner zone, called the region of the coastal water, with 

 comparatively scattered, polar pack-ice and winter fjord-ice. 



This disposition seems to be typical; it is mentioned by earlier 

 expeditions and is certainly caused by the currents. 



The polar drift-ice very seldom came into the fjords inside the 

 outermost skerries, even if there was depth and breadth enough in 

 the mouth of the fjord, in summer because the surface water in 

 there was fresher and had a tendency to go eastwards, and in autumn 

 owing to the presence of the fjord-ice. 



The boundary between the drift-ice and the fast fjord-ice fol- 

 lowed approximately the connecting line between the outermost 

 skerries off the coast and in the mouths of the fjords; the skerries 

 thus acted as a kind of bulwark to keep the heavy drift-ice away 

 from the coast. 



In the summer of 1906 the drift-ice was over 14 km. from the 

 coast until September 19th, when it came close in to land. 



Here it lay closely packed together and frozen solid, and a tidal 

 fissure, which was open most of the winter and which went from Ma- 

 roussia to Sonja Havn in the mouth of Øresund, marked the bound- 

 ary between it and the fast fjord-ice. Sometimes it broke adrift after 

 strong offshore storms and the drift was then always southwards. 



