180 MAEIOX EXPEDITION TO DAVIS STRAIT AXD BAFFIX BAY 



Bank (120). we arrive at an estimate of 1,200 to 1.500 miles as the 

 length of the iceberg train on March 15 (an average date for the 

 arrival of the van on the northern edge of the Grand Bank). On 

 this date according to the assumption the rear icebergs would be 

 about off Cape Dier, Baffin Land. It is not likely that any bergs that 

 are still farther north at that date w^ill drift past Xewfoundland dur- 

 ing the following summer because the coast line and adjacent shelf 

 waters begin to be bared from south to north, as the spring advances, 

 Avith the bergs tending to set on-short after June and so to become 

 trapped. If pack ice were to blockade the Lal)rador and Xewfound- 

 land coasts the year round as it actually does from January to April, 

 icebergs would drift into the North Atlantic throughout the year. 



Pack ice may also tend to keep the icebergs moving faster in the 

 currents than would otherv/ise be the case by holding them just 

 outside the edge of the continent where the drift is most rapid. 

 This banding of the current is well shown in the dynamic topo- 

 graphical map of the Marion expedition for the coasL" of Labrador. 

 (Fig. 95.'^) If, on the other hand, there is less pack ice than usual, 

 the shelf waters are open to receive the bergs, under which condi- 

 tions few of the latter ever return to the main current path. It is 

 apparent, therefore, that the distribution of the pack ice exerts a 

 great influence on the drifv and numbers of icebergs coming out of 

 the Arctic. An example of the foregoing effect was observed in 

 the spring of 1924, a year Avhen no pack ice was sighted south of 

 Newfoundland, and when only 11 icebergs drifted south of that lati- 

 tude, instead of the normal 380 to 400 bergs. This was not due to 

 any lack of glacial ice to the northward as the Tampa on her north- 

 ern cruise that May discovered a large numl)er of icebergs, undoubt- 

 edly the spring crop headed for the Grand Bank, trapped and stranded 

 along the coast from Cape St. Francis to the Strait of Belle Isle. 



ANNUAL VARIATIONS IN THE NUMBER OF ICEBERGS PAST 

 NEWFOUNDLAND 



Great variations have been observed in the number of icebergs 

 drifting out of Davis Strait into the North Atlantic — in 1929 there 

 were over 1,300 to only 11 in 1924. As scientific observer, attached 

 to the ice patrol, I have been concerned with the possibility of de- 

 veloping from these known factors, some method by which a prac- 

 tical forecast of the number of bergs which would drift past New- 

 foundland during the spring might be arrived at. The first part of 

 this investigation centered on a thorough study of similar investiga- 

 tions in the past and a decision of what methods were the most 

 promising. 



Schott (1904), long ago drew attention the the great number of 

 icebergs that came south of Newfoundland during 1903 and dis- 

 cussed the resulting effects. Campbell-Hepworiih (1914), investi- 

 gating the annual variations in the Labrador current compiled a 

 table of the annual amount of icebergs for a 10-year period. 



Mecking (1907, p. 3), with the records of the Deutsche Seewarte, 

 the United States Signal Service, and the United States Hydro- 

 graphic Office, as previously discussed, compiled a record of the 



" Hclland-IIansen and KoefoKl (1909, p. 269) stato that th." sfjiliiis vessels aloiis rlie 

 east coast of Greenland, by forcing themselves into the border of the pack, inside the 

 continental edge, escape the brnnt of the southward current, which i)assed in plain view 

 farther out. 



