The wind acts directly on the subaciial portion 

 of the iccbcrp and indirectly on the subnierjied 

 portion throufi^li the force wiiich it imparts on 

 the ocean surface. The prevailing!; winds alonjj; 

 the eastern (^anadian coast are from tiic nortli- 

 west, whicli are flie most favorable for transport- 

 ing icebergs toward tiie (iiand lianUs. Winds 

 from any other direction tend to impede tiie ad- 

 vance of the icebei'gs. Obviously I lie advance of 

 icebergs would be blocked liy winds from the 

 south. Easterly winds cause the iccl)er<rs to drift 

 toward the Canadian coast wiiere tiiey ground 

 and deteriorate. Westerly winds force icebergs 

 out of the Labi-adoi' Current into the Ijabrador 

 Sea, slowing the icebergs' southern progress and 

 exposing the icebergs to warmer water of the 

 Labrador Sea and wave action. As "Wolford 

 (1972) points out, winds in this region are de- 

 pendent on the location and intensity of the 

 Icelandic Low. This term applies to an area 

 where lows form and intensify rather than one 

 particular low pressure system. Northwesterly 

 winds increase as this low deepens. Normally 

 this low is weak during the summer and intensi- 

 fies during the winter. 



Due to severe low pressure systems (fig. 61), 

 which traversed this region during the winter of 

 1971-1972, the Icelandic Low was more intense 

 than normal for every inontli from December 

 1971 through June 1972 with the exception of 

 April 1972, when conditions were close to normal. 

 During these months, a mean surface pressure 

 anomaly existed as shown in January (fig. 60). 

 Since wind anomaly is related to lines of equal 

 pressure anomaly as winds are to isobars, Buys- 

 Ballot's Law may be applied in determining 

 direction of wind anomaly. During the winter 

 of 1971-1972. the prevailing northwesterly winds 

 were reinforced by the deeper than normal Ice- 

 landic Low'. These winds were extremely favor- 

 able for iceberg drift southward along the 

 Canadian coast. 



Currents 



The Baffinland and Labrador Currents trans- 

 port icebergs soutliward toward the Grand 

 Banks. These currents, which move nuich slower 

 than the wind and are less variable, act on most 

 of the iceberg's surface area. A well developed 

 current system is a necessary but not sufficient 

 condition for a heavy ice year. The Labrador 

 Current was well developed in 1957 (Dinsmore 



et al.. 1958), 1958 (Dinsmore et al., 1960), and 

 1959 (Budinger et al., 1960), but only 1957 and 

 1959 were heavy ice years. In 1958 other ci'itical 

 factors, including warmer than normal sea sur- 

 face temperatures, were unfavorable and a light 

 year resulted. At no time has there been a heavy 

 ice season when the Labrailor Current was not 

 well developed. 



Current data along the Labrador coast are 

 very scarce, especially in the winter months. 

 Russian scientists conducted the only survey in 

 this area during the winter of 1971-1972. P>om 

 their 8-9 November occupation of section 8-A 

 (fig. 63), the volume transport of the Labrador 

 C'urrent was determined to be 6.5 Sv; which is 

 30% greater than normal. Later in the same 

 cruise, section 6-A (14-15 December) and sec- 

 tion 3-A (24-25 December), both of which are 

 farther south, were also occupied. Volume 

 transport was only 1.1 Sv across section 6-A and 

 6.8 Sv which is normal, across section 3-A 

 (Kudlo, 1973). 



On 21-22 March, CGC SHERMAN (^VHEC- 

 720) occupied section A-2 (figs. 14 and 15), and 

 the volume transport was determined to be 2.16 

 Sv southward and 1.07 Sv eastward. This indi- 

 cated that the southerly transport had nearly 

 doubled since the December occupation of 6-A. 

 It should be noted that the east-west portion of 

 A-2 is very similar to the Russian section 6-A 

 and the British Grand Banks-Flemish Cap sec- 

 tion (Hill etal., 1974). 



During a two week period in April, each of 

 these sections was occupied. As part of an IIP 

 survey, section A-2 was occupied on 7-9 April 

 (figs. 25 and 26). The southward flow was 3.71 

 Sv while the eastward flow was 1.70 Sv. On 

 10 April, the southerly flow across section 6-A 

 was 3.03 Sv (Kudlo, 1973). Hill et al. (1974) 

 calculated the southerly flow to be 5.27 Sv from 

 a 17-18 April occupation of the Flemish Cap- 

 Grand Banks section. Two factors may have 

 been responsible for the wide range in these 

 ti'ansport values. First, as has been noted by 

 Morgan (1969) and other IIP authoi's, the vol- 

 ume transport of the Labrador Current may 

 undergo large changes over a short period of 

 time. Second, much subjectivity is requii'ed in 

 using the geostrophic metliod of detei'mining 

 currents especially in extrapolating values in 

 shallow water and in selecting a reference level. 

 As the Flemish Channel is verv narrow and re- 



9 



