and they drifted southward in the cold current. Here we have the 

 only apparent mechanism for delivering bergs to the eastern branch 

 of the Labrador Current; i. e., field ice (wliich is strongly influenced 

 by wind) containing bergs blown southeastward to the northeastern 

 slope of the Banks and there releasing the bergs into the only high road 

 southward to the United States-European lane routes. With the 

 disappearance of field ice from the area and cessation of continued 

 high winds, with the advancing season, tliis means of delivering bergs 

 to the eastern branch of the Labrador Current no longer existed and 

 no more bergs came south in that current. In other words the 10 

 bergs (and 3 more probably from the same source) counted by the 

 patrol vessel on March 29 and 30 were the only bergs to enter the 

 critical area in 1937. 



In attempting to explain why, tliis year, bergs did not drift south 

 in what is considered the normal path along the eastern slope of the 

 Banks it must be realized that the fundamental reason for these 

 seasonal changes are somewhat obscure. The answer lies in the 

 meteorological conditions over the shores of Greenland, Labrador, 

 and Baffin Land and in the ocean circulation in the Labrador Sea and 

 Baffin Bay and their connecting waters. The immediate cause is 

 more readily apparent. Bergs, because of their deep draft and small 

 percentage of area exposed to other influences, are perhaps the best 

 known current indicators or "drift bottles." Following this idea out 

 leads to the conclusion that if 97.2 percent of the bergs south of 

 latitude 48° N., this season came south via the western branch of the 

 Labrador Current west of longitude 50° W., it was because the major 

 portion of arctic water entered the Atlantic by that route this particu- 

 lar year. This unusual flooding of the arctic current around Cape 

 Race will also account for the appearance of ice bergs in the vicinity 

 of latitude 44°30' N., longitude 54°30' W., on two occasions tins 

 season, February 23 and 24, and May 1 and 5. This is a most 

 unusual place to find bergs and it formed an unexpected menace along 

 track E to Halifax. 



This year, as in every other year, an estimated count of the number 

 of bergs driftmg south of latitude 48° N., was made for statistical 

 purposes and to compare with the result of annual forecast of the 

 number of bergs south of that same latitude. Because of the concen- 

 tration of field ice and bergs in the rather small area around Cape 

 Race through which for a good part of March no ships could pass, 

 the problem of estimating the number of bergs and of sorting out 

 repeated reports was even more difficult than ordinarily. However, 

 the forecast for the season of the number of bergs to drift south of 

 latitude 48° N., based on the formula described in Coast Guard 

 Bulletin 19, part 3, pages 180 to 189, was 600 bergs as compared 

 with an estimated count of 470 bergs. 



