Within the boundaries of the ice described above, south of 50°00' 

 N., and east of 52°00' W., the pack consisted of drift ice and open pack, 

 grading to close and consohdated pack west of 52°00' W. North of 

 50°00' N., the ice graded from drift ice east of 54°00' W., to open and 

 close pack west of 54°00' W. 



During the month several flights were also made along the Labrador 

 coast between Belle Isle and Hamilton Inlet to determine the potential 

 supply of ice to the areas traversed by shipping further south. On the 

 9th and 10th of April, the outer limit of Labrador ice was found to run 

 in a line from Belle Isle to 54°20' N., 53°40' W., to 56°00' N., 56°20' 

 W., with many bergs and growlers in the ice. The flight on the 10th 

 also covered the area near ocean station B at 56°30' N., 5l°00' W., to 

 determine if there were any readily apparent explanation for the 

 numerous bergs reported in this locality. On April 14, another flight 

 along the Labrador coast revealed that the pack ice in this vicinity 

 was also moving east, and that the outer limits were defined by a hne 

 from Belle Isle east to 55°00' W., to 52°20' N., 53°40' W., to 53°40' 

 N., 53°30' W., to 54°50' N., 54°30' W.. to 55°05' N., 56°50' W., 

 thence north-northwest. Many bergs and growlers were also found 

 within the limits of this ice. 



On April 1 the Canadian Department of Transport began daily 

 aerial surveys, weather permitting, of the Cabot Strait and Gulf of 

 St. Lawrence area. On the 7th, the St. Lawrence River was reported 

 navigable to Quebec, and by the 14th, navigable to Montreal. By the 

 17th of the month the ice in Cabot Strait had drifted to its maximum 

 easterly extension, under the influence of the westerly winds. On this 

 date open pack and drift ice extended from Cape Breton to a line from 

 St. Paul Island to 46°20' N., 57°40' W., to 45°35' N., 57°40' W., to 

 45°20' N., 58°30' W. Some scattered drift ice was also reported 

 between St. Paul Island and Cape Ray, but did not prevent passage 

 through this area. By the end of the month most of this ice had 

 disappeared, leaving only isolated patches off the east coast of Cape 

 Breton. Routes via the Strait of Canso and Northumberland Strait 

 were reported clearing, but not recommended as yet for navigation. 



During March and April numerous bergs were reported in the 

 vicinity of ocean station B at 56°30' N., 51°00' W., by Coast Guard 

 cutters occupying the station. At the request of Commander, 

 International Ice Patrol, several of these bergs were tracked contin- 

 uously until they disintegrated, in order to determine if they were 

 moving into this locality with a definite current, or were merely 

 following the wind. One berg was tracked continuously from April 

 11 to April 21, following a ro uglily circular path with an average 

 diameter of about 50 miles. An analysis of this drift is considered in 

 detail in the section on oceanography. 



Twelve aerial surveys were made by Ice Patrol aircraft during 

 April. It is estimated that 12 bergs came south of 48°00' N. during 



260173—54- 



