NORTHERN ICEBERG SURVEYS 

 BACKGROUND 



The very existence of the International Ice Patrol is due to the fact 

 that icebergs threaten transatlantic shipping in the vicinity of the 

 Grand Banks each spring and early summer. The mission of the Ice 

 Patrol and its operations are based on the behavior of icebergs. A 

 study of annual ice conditions since the inauguration of the Inter- 

 national Ice Patrol in 1913 readily reveals that no two ice seasons are 

 exactly similar, each having its own peculiar characteristics. It is 

 true, however, that some generalities can be made. For example, the 

 iceberg threat to shipping on the Grand Banks is usually confined to 

 the montlis March through June, with the heaviest threat usually in 

 April and May. Bergs are transported from the north in the Labrador 

 Current and tend to be mainly concentrated in or near the Current 

 and its branches during the ice season. Yet one wonders and marvels 

 at the extreme fluctuations that can and have occurred from one year 

 to the next. One needs only go back to 1957 and 1958. The year 

 1957 was one of the worst iceberg seasons on record, with over 900 

 bergs drifting south of the 48th parallel of latitude from January to 

 August and hundreds of them invading the shipping lanes on or near 

 the Grand Banks. The next year only one berg managed to drift 

 south of 48° N., with no threat to the major lanes. 



Why such a fluctuation from one season to the next? This question 

 has been pondered by many who have been associated with the Ice 

 Patrol over the years. Unfortunately, ice observation in areas up- 

 stream to the source of icebergs has been very scanty over the years, 

 collecting insufficient data for determination of the facts which will 

 allow proper analysis and yield an educated answer to the above ques- 

 tion. In addition to the purely scientific reason of a search for more 

 knowledge, surely the International Ice Patrol could perform more 

 efficient services if more information could be obtained about bergs, 

 their origin, their lifetime experiences, their characteristics, and reasons 

 why they appear when they do near the Grand Banks to menace 

 shipping. 



Until more facts are obtained, some assumptions must be made. 

 It would seem an oversimplification if the weather were to be blamed 

 for these fluctuations, yet this is generally true. Certainly oceano- 

 graphic factors must also be considered as, after all, the system of 



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