The Baffin Bay Pack - The Baffin Bay Pack Is east of the fast ice 

 which extends the length of the Baffin Island coast north of Cape Dyer 

 and By lot and Devon Islands, It forms in the northern area during the 

 early weeks of October, expands southward and encloses all of the waters 

 of Baffin Bay and central and western Davis Strait in November. Its 

 composition and structure has many local variations. The Baffin Bay Pack 

 contains floes of different sizes, thicknesses, great pressure ridges, 

 young ice, polar ice, and ice of land origin. The pack grows in size 

 during winter. Storms will cause fragment shifting of the pack and the 

 opening of great leads. New and winter ice are compressed and pressure 

 ridges are formed. Large sections of the pack drift southward through 

 Davis Strait, enter the Labrador Current, and the newly exposed water 

 areas acquire new layers of ice. Therefore, because Baffin Bay and Davia 

 Strait ice is replenished constantly through the season of growth, the 

 pack is vast and heterogeneous. 



Because of geographic dissimilarities, the pack can be separated into 

 two sectors: the southern sector extends from Cape Dyer to the latitude 

 of Home Bay, and the other section, to the north of this latitude. The 

 southern sector responds more readily to changes in pressure. Strong 

 northerly winds cause very broad east-west leads that extend nearly the 

 width of the pack. They may form singly, or in a parallel series separated 

 from each other by wide bands of densely concentrated floes. Winds of a 

 westerly component produce short, narrow, and irregular leads with a gen- 

 eral north-south orientation. Finally, the coastal blocking of Cumber- 

 land Peninsula and other controlling factors bring about th<* formation of 

 polynyas and many small leads in the area northwest and east of Cape 

 Dyer which will close upon the slightest change in th« condStlon of the 

 pack. 



During the months of intense ice production, January through mid- 

 April, npwly opened leads readily freeze. Within a few weeks they may 

 acquire a layer of ice 18 inches or more thick. However, renewed stresses 

 on the ice br^ak up the new ice into floes of different sizes which mix 

 with the surrounding ice of the pack. 



The western side of the pack ice contains floes of hummocked polar 

 ice and floes that are extremely rough and very heavily laced with pres- 

 sure ridges. Some of the ridges exceed 10 feet in height. Also found in 

 this area are floes whose surface features resemble a consolidated mass 

 of crushed upended blocks. On the other hand, the eastern side of the 

 pack contains a high percentage of giant floes in which pressure ridges 

 are widely separated; the surface of the ice between them is relatively 

 smooth. These floes have frozen within them smaller flop-s of thicker ice 

 whose ridges protrude above the surface and often escape detection owing 

 to the snow layer that covers them. 



Thickness of the ice in this sector of the pack is variable. Older 

 ice, formed in autumn, attains a thickness of more than 30 inches by 

 January, and may exceed U feet by March. Within this pack thin ice is 

 found which formed recently in leads or polynyas. 



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