23 



Baffin Bay, the number diminished thereafter. In general appearance 

 also, the bergs off Baffin Land did not have the sharply chiseled out- 

 hnes and the newness of those, Disko to Cape York. Released in July 

 and drifting at the rate of 7 to 8 miles per day (see current map, 

 Bullethi 19, pt. 3, p. 140) the vanguard of the 1940 iceberg procession 

 might quite plausibly have been in the northern part of Baffin Bay 

 in mid-September. Predicted positions based upon the average laiown 

 velocity of the Baffin Land and Labrador Currents indicates that 1940 

 Greenland icebergs will be in the vicinity of Cape Dier, Baffin Land, 

 the first part of December; oft" Belle Isle in February 1941, and arrive 

 in the vicinity of the Grand Banks in April. The iceberg train thus 

 assists to give a seasonal complexion to the ice menace off Newfound- 

 land for the months of April, May, and June. 



It should not be inferred from the foregoing that the bergs drift 

 with clocklike regularity, for it is known that only one berg in more 

 than 20 succeeds in drifting south of Newfoundland. The vicissitudes 

 of winds, currents, and coast lines, tend to disrupt and obscure the 

 original grouping which the bergs received as a result of seasonal re- 

 lease from the fiords. Pack ice probably exerts the most dominant 

 control as it impresses its own seasonal cycle on that of the bergs. 



The winter production of pack ice (west ice of the Greenlanders) 

 appears normally in October and November in Baffin Bay and drifts 

 rapidly southward continuing to swell and to spread to greater and 

 greater extent. (See fig. 14.) West ice normally appears off Uper- 

 nivik in December and often off Holsteinsborg in January (p. 25). 

 The Polaris party drifted on a floe in this seasonal field from Smith 

 Sound, October 15, 1872, through Baffin Bay and Davis Strait, and 

 were rescued off Newfoundland, April 30, 1873. Under the tangential 

 driving force of strong northwesterly winds the west-ice pours south- 

 ward through Davis Strait about the first of December entangling and 

 carrying along with its fields, bergs from the previous summer's crop 

 from West Greenland. (vSee fig. 16.) A very high correlation coeffi- 

 cient between pack ice and icebergs indicates (other things being equal) 

 that an abnormal amount of pack ice in Baffin Bay and Davis Strait 

 will be followed by an abnormal number of icebergs off Newfoundland. 

 Thus from the 6,000 bergs estimated afloat in Baffin Bay the fall of 

 1940, the pack ice and the currents will select the number to menace 

 the North Atlantic steamship lanes in 1941. 



Three of the important variables are (a) pack ice ; (6) winter atmos- 

 pheric circulation over the Labrador region; and (c) the production 

 of icebergs.^ "^he importance of pack ice as an accessory to the ice- 

 berg menace in the North Atlantic was emphasized long ago (Bulletin 

 19, pt. 3, p. 179), but advanced information regarding the varying 



« Another suspected factor being tested is the variation of heat transport of the West Greenland Current 

 into the Labrador Sea. 



