54 MAEIOX EXPEDITION TO DAVIS STEAIT AND BAFFIX BAY 



Hemisphere. In heavy ice years the pack lengthens out in h^ng strips 

 (see fig. 5, p. 16), and chains paralleling the edge of the bank. i. e.. the 

 direction and flow of the current, as far south as the " Tail " on the 

 forty-third parallel. The farther southward the pack drifts the 

 more open it becomes and likewise the shorter time it lasts. South of 

 the forty-fourth parallel it is very patchy and dismembered, surviv- 

 ing only a day or two. The latter part of March and the first of 

 April witness the deepest southern invasions.*" 



Scattered floes from the ice tongues are continually being broken 

 away Ijy the prevailing westerly gales and driven across the continen- 

 tal edge into deep water, where the ocean swell and warm surround- 

 ings rapidly melt them away. A ship may report sighting patches of 

 pack in the morning, while another vessel passing the locality in the i 

 afternoon may see no signs of it at all. It is a well-established fact 

 that pack ice rarely, if ever, extends Avestward around the Tail of the 

 Grand Bank. Although the cold current might tend to carry the 

 ice in such a direction the strong westerly winds prevailing at this 

 time of the year are dominant. A floe of pack ice was reported to the 

 ice patrol in March, 1924, as 120 miles southeast of the Tail of the 

 Grand Bank. 



The fields on the Grand Bank reach a maximum during April, 

 after which they recede, and by the latter part of the month or the 

 first of May extend no farther south than the northeastern part of 

 the Grand Bank. Under favorable conditions small fields of pack 

 may be sighted occasionally along the northern slopes of the Grand 

 Bank throughout May, but finally summer temperatures cause its' 

 complete disappearance. The distribution of pack ice tends to follow 

 the primary circulation of the water, which over the N^ewfoundland 

 Banks progresses as a number of vortices, one spilling over into thei 

 other. The winds always exert a great effect, tending to mask that 

 of the currents. A characteristic emliayment in the pack ice on 

 the Grand Bank is nearly always to be observed over the southwest- 

 ern slojDe, as shown on Figure 2T, page 53, where unmistakably 

 warmer Avater floods in from oif-shore. 



Altliough in the open Atlantic the pack tends to scatter and' 

 many floes to drift away from the main fields, the ice, nevertheless, 

 retains considerable strengtli and is still an imposing spectacle. On 

 the Grand Bank, even as far south as the forty-fifth parallel, ships 

 may easily become imprisoned, with no water from tlie masthead asj 

 far as the eye can see. 



If we examine a few of the glacons in more detail, we find that 

 all exhibit a more or less tabular shape, with some of the older pieces 

 hummockecl in round uneven contours. The glacons on the outen 

 edge of the pack, and scattered here and there in the open water, i 

 show evidences of the greatest deteriorations. ^Melting, however, of i 

 all the ice ]>rogresses much faster at the water line than above or 

 below, resulting in characteristic tabular and hourglass shapes. Thei 

 thinner, suialler ])ortion is always U])permost, not only on account 

 of e(|uilibrium but also because tlie ])ortion exposed to the air amli 

 to the sun in the cold water of spring melts faster than the parti 

 below Avater. The outward sloping form of the submerged under- 1 



<» According to the Doutsche Sccwarto the most soutlioiiv iiciietration of pack ice was 

 in .\pril. 1S87, May. ISSr., and June, ISSi.' and ISS."., wlien it was sighted on the fortieth 

 paralli] near lona:itiide 40°. I 



