52 



MARIOX EXPEDITION TO DAVIS STRAIT AND BAFFIN BAY 



latitude of St. Johns, Newfoundland. 1 to ^ inches in thickness, and 

 out from the coast for a distance of several miles. Rodman (1890, 

 p. 2G) has published a table showing the ap})roximate dates of ap- 

 pearance and disa})i)earance of ice aloii^- the Labrador and Xew- 

 foundland coasts. 



On several previous occasions in discussino: certain re<_nons we have 

 called attention to the importajit influence which bathymetrical con- 

 ditions have on ice distribution. The Labrador shelf is no exception 

 to the rule, providing a high road, so to speak, along which the pack 

 may easily advance to lower latitudes. The bathymetrical map of 

 Davis Strait shows that the Labrador shelf is much wider than that 

 iilong the other coasts of this region. It nniintains an average width 

 of 80 miles, as determined by the r)00-fath(>m isobath, from Cape 

 Chidley, Labrador, southward to Hamilton Inlet, thence to the lati- 

 tude of Cape Race it spreads out very wide: for exam])le. off St. 

 Johns it measures nearlv i^SO miles. The breadth and wneral ont- 



The Offing of the Labrador Coast in June 



Figure 2(i. — The procession of pack ice wliicli is continually being Ixirne sovit'.'.w^ird 

 along the Labrador coast for seven months of the year by the cold current. This 

 coastal lielt of pack ice is claimed to play an important role in the southward 

 distribution of the icebergs, they being fended off the coast and kept out in the 

 cold current. (Photograph by E. M. Kindle.) 



line of the east North American pack along this coastal stretch is 

 largely a reflection of the depths. In years of abundant pack, the 

 outer edge of the field off St. Johns has been recorded a hundred or 

 two hundred miles from the coast. 



As summer advances, the pack melts back toward its northern 

 roots uncovering first the Newfoundland and then the Labrador 

 coast lines. The Strait of Belle Isle is usually open to navigation 

 from July to December, the first of the trans-Atlantic steamers en- 

 tering June 15 to July 1 and the last passing out the first week in 

 December. The Labrador coast is often free of pack ice, at least for 

 navigation, during Julv, while in other summers the coast has been 

 continually hampered.''® 



=8 An excellent example of the rate of dissipation of the Labrador pack is afforded by 

 the fact that the Godthaab expedition in early June, 1928. found a field of pack ice ex- 

 tending along a large part of the Labrador shelf of 18,000 square miles area, but six 

 weeks later the Marion expedition found these waters clear and all ice disappeared. Pack 

 ice in the western Xorth Atlantic was markedly below normal the year of 1928. 



