ICE CONDITIONS AND THE ENVIRONMENT 



Dnrino; the period 1 September 1968 to 30 Au- 

 gust 1969 an estimated total of 57 icebergs drifted 

 soutli of 48° N. Table 4 shows the monthly statistics 

 for this period. 



Preseason aerial ice reconnaissance of Baffin Bay 

 in late September and eai'ly October of 1968 indi- 

 cated the possibility of a heavy ice season on the 

 Grand Banks in the spring of 1969. Figure 1 shows 

 the distribution of approximately 10,000 icebergs 

 observed during the reconnaissance. Except for the 

 areas along the Greenland coast and between 

 Greenland and Ellesmere Island, the counts indi- 

 cated on Figure 1 are probably accurate within 

 ±10 percent. In areas along the Greenland coast 

 and between Greenland and Ellesmere Island, the 

 berg count could be low by up to 100 percent be- 

 cause of inaccuracies in the method of visually 

 sampling and estimating counts. About 5,000 ice- 

 bergs were counted in these two areas, however 

 there may actually have been up to 10,000 icebergs. 

 Allowing these assumptions, a total of up to 15,000 

 icebergs could have been present in Baffin Bay dur- 

 ing the survey. The figure 15,000 is in general 

 agreement with that obtained on the complete sur- 

 veys made in 1948 and 1949. No significant 

 amounts of sea ice were observed on the survey. 



Some indication of the movement of icebergs out 

 of Baffin Bay is shown in Figure 2 which presents 

 smoothed contours of iceberg density (icebergs per 

 square "mile) on the September/October 1968 sur- 

 vey. As can be seen in the figure, four general paths 

 of iceberg movement appear to be; (1) southwest- 

 ward from the Disko Bay area, (2) westward from 

 the Unamak Fjord area, (3) southwestward from 

 eastern Melville Bay, and (4) westward along the 



Greenland coast from western Melville Bay and 

 tlie Thule area until the Canadian coast is reached 

 where the icebergs move southward. These paths 

 are shown on Figure 2 by the letters A, B, C, and 

 D respectively. These paths are in general agree- 

 ment with previously reported ideas of iceberg 

 movement and ocean currents. 



Figures 3 through 6 show the development of 

 the ice season, as obsei-ved on preseason surveys. 

 The purpose of these preseason surveys was to both 

 guard against the possibility of an undetected in- 

 trusion of icebergs into the Transatlantic shipping 

 lanes, and to collect data on iceberg distribution. 

 The icebei-g distribution observed during the 

 flights of 19-21 February (Figure 5), confirmed 

 the growing belief that the expected heavy ice 

 season would not be forthcoming. On 26 February 

 1969 Coimnander, International Ice Patrol dis- 

 seminated a special ice bulletin wherein a light 

 ice season, with less than 100 icebergs drifting 

 south of 48° N., was forecast. 



The development of the ice season after the 

 commencement of Ice Patrol ser\-ices on 15 March 

 1969 is shown in Figures 7 through 13. Figures 

 14 and 15 show the observations made on a series 

 of postseason flights in August 1969. In general 

 the m. "ment of icebergs during the season ap- 

 peared to follow the nonnal paths. The number of 

 icebergs drifting south of 48° N. was less than 

 normal. Fifty-seven icebergs drifted south of 48° 

 N. in 1969 versus a 24-year average (1946-1969) 

 of 222 icebergs. The southernmost extent of ice- 

 bergs this year, 43°50' N., was about the same as 

 the 1945-1965 average of 43°36' N. The southern- 

 most extent of sea ice to about 48°30' N., 50°30' W. 



Table 4.— Estimated Number of Iceberss South of Latitude 48° N, 1969 



Note.— Complete statistics for the period 1900 to 1968 are given in Report of the International Ice Patrol Service in the North Atlantic Ocean, Season of 



196S (CO 188-23). 



15 



