value of which, expressed in knots, has been listed in the following- 

 table along with the average gradients of barometric pressures in 

 millibars per nautical mile and the resultant of direction of the wind 

 drift in degrees true estimated as described above. 



From this table it can be seen that in March the wind drift was 

 oifshore into warm waters and that in April it changed almost 180° 

 to onshore. Figure G illustrates this table graphically. Thus, for two 

 successive months the wind drift was such that it contributed 

 markedly to the destruction of ice. Tlie offshore wind in March 

 drove sea ice, and to a lesser degree bergs, offshore into warm water 

 where a large amount of ice supposedly melted. In April the effect 

 of the wind was to drive most of the remaining bergs onshore where 

 they were so eroded that they were not large enough to make the 

 long journey to the Grand Banks during the months of May and 

 June. 



A more compreliensive discussion of the effects of wind drift at 

 this time is precluded because synoptic charts for the months prior 

 to March 1949 were not available. 



ICE CENSUS 1949 



Between 10 August 1949, and 18 August 1949, two PBlG (flying 

 fortresses), with the USCGC Winnebago acting as a weather re- 

 porting station, and a plane guard carried out an ice census of the 

 Baffin Bay region. This was the second aerial ice census of Baffin 

 Bay undertaken by the TJ. S. Coast Guard in furtherance of the long- 

 range scientific program of the International Ice Patrol. Difficulties 

 encountered during the 1948 ice census, especially the problems in- 

 volved in a photographic analysis of the ice census, were eliminated. 



Heretofore visual counts of the icebergs in this area had been made 

 in 1940 and 1948. In 1940 the count had been made from a Coast 

 Guard cutter circumnavigating Baffin Bay and in 1948 by two PBlG 

 airplanes. The total count in 1940 was a combination of visual sight- 

 ings and estimates by experienced observers. The count in 1948 "was 

 based on visual sightings with less emi^hasis on estimates b}^ trained 

 observers. In 1949 the count was based on visual sightings, radar 

 counts (approximately one-sixth of the census area was searched by 

 radar alone because of poor visibility), and photographs of large 

 concentrations. This latter count, while subject to certain limitations 

 of the equipment involved, was by far the most accurate that has been 

 obtained. A total of 40,232 icebergs were counted in 1949 as com- 

 pared to 12,128 in 1948 and 3,289 in 1940. A visual count made in 

 1949 before the photographs were developed indicated 17,500 bergs 

 in Baffin Bay. If nothing else, these different counts proved that 

 photographs were necessary if an accurate ice census was to be 

 obtained. 



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