overcome any restraint of one on the other. Does the pack ice cause the 

 berg to move faster by transferring some of the forces acting on it or 

 does the pack slow the berg down by acting as a restraint and resisting 

 the motion of the berg ? On the basis of aerial observations, wakes of 

 bergs in the pack ice are generally downwind indicating a faster 

 movement of the pack ice due to wind. This would indicate that 

 generally bergs in pack ice are pushed by the pack ice with the wind. 

 However, most pertinent is the probability that, in spite of sea ice 

 pushing and assisting in the transport of icebergs, an extensive cover 

 of sea ice upwind may really act as an indirect deterrent to berg 

 movement by preventing wind driven currents to be generated. The 

 assumed deterrent effect of sea ice on the generation of wind driven 

 currents is probably most pronounced for alongshore or offshore 

 winds. This may render difficult any significant berg movement sea- 

 ward and consequent elimination from the Labrador Current, The 

 point is that the downwind push of sea ice on bergs may not com- 

 pensate for the loss in berg drift due to the prevention of wind driven 

 currents being generated in extensive sea ice areas. Wind driven 

 currents from onshore winds would conceivably be generated even 

 though less effective. Thus onshore winds are more likely to ground 

 bergs than offshore winds are likely to drive bergs out of the current 

 system. The affect of pack ice acting as a fender along the coast to 

 reduce stranding of bergs must also be considered. Smith assumed 

 this effect to be of paramount importance. See Bulletin 19 in this 

 series. Smith's berg forecasting formula included a parameter for 

 sea ice because of this assumed buffer action on the part of sea ice. 

 Smith believed that the greater the sea ice, the lesser the number of 

 stranded bergs. While this is probably true, it is suggested that the 

 main reason for the excellent correlation between the relative abun- 

 dance of sea ice and the relative number of bergs reaching the shipping 

 lanes is the berg preservation characteristic of sea ice. Considerable 

 evidence from Ice Patrol seasonal flights in the Grand Banks, New- 

 foundland, and southeastern Labrador coast and limited evidence 

 from northern ice surveys all indicate that pack ice will be driven close 

 ashore and bergs contained therein will be stranded by sustained on- 

 shore winds. As winds become offshore, pack ice will once more drift 

 out to sea, as will most of the bergs, to once more be swept along by the 

 Labrador Current toward the Grand Banks. A restraining force is 

 probably exerted on bergs by pack ice depending upon thickness and 

 concentration, but it is known that onshore winds of sufficient force 

 and duration can overcome the sea ice fender affect. It is emphasized 

 that this discussion relates to the sea ice effect on the next season's 

 Grand Banks berg crop south of Cape Dyer. No attempt is made here 

 to assess the effect of pack ice on the movement of bergs in Baffin Bay 



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