of 8, 7 and 6 days; the remaining intervals being 5 days or less. 

 The longer intervals occurred more in late season than in early 

 season. This was due not only to the greater prevalence of fog 

 in the Grand Banks region during the latter part of the season, 

 but also to the increasing distances from the base field to the search 

 areas as the bergs scattered with the advancing season. 



Parallel search courses usually were laid out 25 miles apart on 

 the basis of 15 miles being the limit of reliable observation. Alti- 

 tudes of 1,500 to 400 feet were more common than higher altitudes. 

 Visible contact with the surface was maintained where practicable. 

 Without contact conditions a minimum assured altitude of 400 feet 

 is essential because of the hazard of collision with lofty bergs. 

 During the early part of the season icing conditions frequently 

 controlled flight levels. Emphasis was placed on accurate naviga- 

 tion and in this connection Loran is considered essential equipment. 

 The use of radar in aerial ice reconnaissance is discussed in another 

 section of this report. 



ICE CONDITIONS IN 1946 



January 



An unknown ship reported a piece of ice or a berg at 41°57' N., 

 49°26' W., on 2 January. It is considered that the position as well 

 as the type of this ice is doubtful. No other ice was reported until 

 the 31st when another ship reported a large field of pack ice 115 

 miles east of Cape Freels, Newfoundland. No known bergs drifted 

 south of the 48th parallel during January. 



February 



Patches of field ice, which were apparently the eastern edge of 

 the Labrador pack, were reported along the 50th meridian from 

 50° N., to 52° N., on the 1st. This moved southward until on the 

 6th an ice patrol flight found the southern edge of the field ex- 

 tending from Torbay Point, Newfoundland, easterly to about 

 48° 15' N., 49°40' W. The outer half of the field was loose with 

 about five-tenths to six-tenths cover while the inner part was close 

 packed but lighter. The field ice continued to move southward and 

 to spread southeastward developing two tongues, one between 

 longitudes 51° and 52° W., which reached the latitude of Cape Race 

 by the 13th, and the other along the 100-fathom curve along the 

 eastern edge of the Grand Banks. This first ice to arrive was un- 

 usually free of bergs and growlers and such as were present were 

 mostly in the heavier ice of the offshore margins. During the 

 second half of the month the southern edge of the field ice receded 

 northward until on the 27th only light slob and slush was present 

 south of 48° 30' N., and that was between the 52d meridian and 



740743—47—9 



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