SCIENTIFIC RESULTS 55 



body easily exphiins its most serious threat to tlie propellers of ships. 

 Ill advanced sta<j:es of ineltino- the jilacoiis show many gracefully 

 rounded erosions, and continual licking of warm waves sculptures 

 the ice into fantastic shapes. 



GTLF OF ST. LAWRENCE PACK 



Pack ice from along the coast of Labrador enters through tiie 

 Strait of Belle Isle into the (nilf of St. Lawrence. How much enters 

 is problematical I)iit undoubtedly the indraft is greatest with easterly 

 winds when a continuous flood current has been observed for the 

 ])eriod of a month. Westerly winds on the other hand tend to drive 

 the ice oil' into the Atlantic and to set n\) an outflow^ of the water. 



^^u^uj^M 



'^^Mg.l.*« wiy * t ! g - 





Pack ice Spreads Over Grand Bank South of Newfoundland 



Figure 28. — Pack ice is carried ovei- a tliousaiul miles southward out ot Davis 

 Strait and into the North Atlantic every spring. The duration of pack ice so 

 far south is a matter of a few weeks only. This photograph was taken April 9, 

 1921. in latitude 4.">'' 50' N.. longitude 49° 20' W. A seal can be seen in one 

 of the floes. (Official photograph, international ice patrol.) 



The normal circulation in the Strait of Belle Isle is an indraft 

 along the Quebec shore, and an opposite set along the Xewfound- 

 land side. From December to July, however, pack ice is liable to be 

 carried into the gulf, the largest contributions tending to hug the 

 Labrador coast on the northern side of the strait. Huntsman (1930, 

 p. 6) relates an occurrence in June, 1897. So much of the pack was 

 brought through the strait by favorable winds that Ashing was inter- 

 I'cred with for a distance of 150 miles around, although the wdiole 

 gulf had previously been open. If this can happen in summer, a 

 natural query is, how much greater quantities must enter during 

 winter, when conditions are probably more favorable? 



River ice, gulf ice, and Davis Strait ice are mixed to form the 

 liulf covering. But in wdiat proportions these mix there, is not 



720860—31 .-. 



