ICEBERG OCCURENCE BY YEAR AND MONTH 1900 1959 



A graph of the number of icebergs drifting south of latitude 48° X. for 

 the years 1 900 to L959 is shown by figure 20. This number is the measure 

 by which t he lee Patrol determines the severity of a year and is the 

 quantity which lee Patrol officers and others have endeavored to predict 

 by the use of various oceanographic and meteorologic parameters. Dis- 

 cussions of methods and formulae are contained in previous bulletins of 

 this series. To date no satisfactory means has been yet devised which 

 enables the intensity of an iceberg season to be forecast well in advance. 

 Work in this held, however, is continuing. 



The average number of bergs appearing south of the 48th parallel each 

 year since 1900 is about 400. The heaviest year was 1929 with 1,352 bergs 

 and the lightest was 1958 when only one berg drifted south. The 693 

 bergs observed in 1959 make this year rank 12th since 1900 and second 

 since World War II. 



The advent of aerial ice observation in 1940 brought about a substantial 

 means to accurately determine the annual count. Prior to then the figure 

 was reckoned from ship reports which contained many duplications. This 

 was somewhat compensated for by unreported bergs but, nevertheless, 

 pre-1946 figures are not entirely comparable with later ones. 



Conditions by months for the years 194(5-1959 are given in figure 21. 

 The months March-July only are presented since these contain 93.5 

 percent of the total number of bergs and constitute the so-called "iceberg- 

 season." 



An examination of figure 21 shows that April is, on the average, the 

 most severe month but is followed very closely by May. June ranks third. 

 This differs from prior years wherein records indicate May to be the 

 heaviest. Regardless, experience has shown that the peak period for ice- 

 berg occurrence is usually from the middle of April to the middle of May. 



ICE REPORTS 1959 



During the 1959 Ice Patrol Season 7,405 ice reports of all types were 

 collected and an additional 251 were received in the remainder of the 

 year thus making a total of 7, 050 for 1959. This figure represents the 

 highest number of reports ever recorded by International Ice Patrol. 



An interesting comparison is with the 1957 season when a greater 

 number of icebergs drifted south that year, but almost twice as many 

 iceberg reports were received in 1959. Since the number of ships reporting 

 both years is about equal, the probable explanation is that greater con- 

 centrations of bergs existed in shipping routes in 1959, and an increased 

 cooperation on the part of all observers. 



Commander, International lee Patrol is grateful to the many masters 

 and officers of ships who have, painstakingly and accurately, reported ice 

 encountered. Records of the Ice Patrol reveal the names of ships and 

 mariners repeated throughout years dating back to the foundings of the 



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