quantitive analysis of the parameters becomes difficult. Instead, the 

 use of accumulated frost degree days of selected stations can be used 

 to describe the general climatology of the area for an indication of ice 

 formations, growth, and attainment of concentrations of field ice, and 

 this measure is used to define, in a general consideration, the berg 

 environmental conditions. Bulletin No. 50 of this series presents a 

 fuller discussion on this subject matter. 



Table 3 lists frost degree days accumulation for the winters 1956-65. 

 Table 4 lists mean monthly frost degree days accumulations from 

 October through 15 March. 



A comparison of the 1964-65 accimiulated frost degree days with 

 the 1956-64 mean frost degree days for the stations from Cartwright 

 north is indicative of a normal winter climate. The slightly warmer 

 than normal indicator for St. Anthony can be correlated to the higher 

 than normal air temi^eratures noted in Newfoundland and southern 

 Labrador in late February and early March. While it is apparent that 

 no direct correlation can be made using frost degree days alone to the 

 average for 1956-65, there is an indication, provided by the years 1957, 

 1959 and 1964, that a greater than normal accumulation of frost degree 

 days, particularly from Hopedale south, is required to provide the 

 right environmental conditions. Another assumption that can be 

 made is that the climatology of the area north of Resolution Island is 

 such that little or no berg deterioration can be expected throughout 

 November to March. Temperature throughout this area remains low 

 enough throughout this period to preclude any noticeable berg de- 

 terioration that can be correlated to mean frost degree days. Even 

 an appeciable reduction in frost degree days could still indicate well 

 below freezing (below 23° F) temperatures. 



THE EFFECT OF SELECTED MONTHLY MEAN SEA LEVEL ATMOSPHERIC PRESSURE DISTRIBU- 

 TION ON THE GRAND BANKS ICE SEASON 



The study of the effect of mean surface wind, as indicated by the 

 U.S. Weather Bureau monthly sea level atmospheric pressure charts, 

 on the drift of bergs from Baffin Bay to the Grand Banks requires the 

 additional knowledge of the distribution of bergs, both by size and 

 location. Special northern ice reconnaissance flights are made to 

 determine the berg distribution. As the area encompassed by the 

 bergs is vast, and as the pressure distribution might vary consider- 

 ably from the northern to tlie southern areas, the bergs that pose a 

 potential threat to the Grand Banks from March to July have been 

 divided into two groups. The first group includes those bergs located 

 between Hudson Strait entrance to Cape Dyer in early November. 

 The second group includes tliose bergs located between Cape Dyer 

 and Bylot Island, also in early No\'ember. The successive monthly 



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