the field ice and bergs had reached approximately latitude 47° N. when 

 strong southerly winds on 4-5 April drifted the ice north of latitude 

 48° N. By the 22d of April the ice liad again drifted south of latitude 

 48° N. when again strong southerly winds completely deteriorated the 

 field ice and, in combination with the eastern branch of the Labrador 

 Current, produced a drift vector that moved the bergs, then poised to 

 enter the steamer tracks, north of latitude 48°30' N. and eastward 

 out of the core of the Labrador Current. 



Other than those already on the Grand Banks, only a few bergs could 

 survive the transit to the Tail of the Banks. The seasonal pattern 

 for 1965 had developed and completed its cycle by mid-May. No 

 further serious threat to the Trans-Atlantic Lane Koutes could de- 

 velop. On 6 June the 1965 International Ice Patrol was terminated. 



Table 1. EsHmated number of itebergs south of 48° N., 1900-1965 



Notes 

 1, Totals for 1946-65 are based mainly upon Ice Patrol aircraft reconnaissance with heavy reliance on 

 ™" Totals lor 1900-1945 are based mainly upon ship reports of other than Ice Patrol vessels. 



AERIAL ICE RECONNAISSANCE 



Thirty-five ice observation flights were made in two Lockheed Her- 

 cules (HC-130B) aircraft by the United States Coast Guard Air 

 Station at Argentia during the ice season. These flights averaged 

 1,230 miles in length and 5.2 liours long. The longest flight was 1,840 

 miles in length. Included are three northern flights to Hudson Straits. 



The primary objective of the aerial ice reconnaissance was to guard 

 the southe'astern, southern and southwestern limits of the ice-encum- 

 bered area in the vicinity of the Grand Banks so that shipping might 

 be advised of the extent of that dangerous area. In addition, the aerial 

 ice reconnaissance had the purpose of maintaining, insofar as visibility 

 conditions and aircraft availability permitted, detailed up-to-date in- 

 formation of the ice situation in the Grand Banks region and north for 

 the benefit of mariners traversing the ice area. Ice reports from ship- 

 ]3ing were of invaluable assistance in attaining these objectives. 



The flight plans were usually made up of a system of parallel lines 

 spaced at 20 or 25 mile intervals depending on visibility. This spac- 

 ing was predicated on the ability of readily sighting bergs at 15 miles, 

 hence, it provided a margin of overlap on parallel tracks and covered a 

 sufficiently large search area. From past experience it appeared that 



