core of the Labrador Current for three 2- week periods in April, May, 

 and June. For the first time a computer was used aboard the Ever- 

 green to make computations previously made by hand thus speeding 

 up the process of construction of the dynamic topographic current 

 charts. Isotherm charts based on the average centigrade temperatures 

 from the sea surface to 150 meters were constructed for each oceano- 

 graphic survey. These charts permitted more accurate forecasting 

 of ice conditions than was previously possible. See Figures 11-15. 

 For a detailed discussion of oceanographic operations see U.S. Coast 

 Guard Oceanographic Report CG-373-10. 



Although the coastal regions of eastern Newfoundland and the 

 northern Grand Banks contained many bergs from early March 

 through June, the Tail of the Banks had a relatively light ice year 

 with no bergs drifting south of 43° N. An estimated total of five 

 bergs crossed south of 44° N., all within a 4-week period from early 

 May to early June. Most important is the fact that the major United 

 States-European shipping Tracks B and C, when in use, remained 

 ice free, although a threat of major proportions existed in April and a 

 minor threat existed during May and June. These threats did not 

 materialize due to the prevailing winds. The sea ice on the Grand 

 Banks was slightly heavier and more extensive than normal. 



The preseason northern iceberg survey on 27-28 February indicated 

 that the Grand Banks potential was about 10 times the potential of 

 1963, a very light berg year. Climatological conditions upstream in 

 the Labrador Current along the Labrador and Baffin Island east 

 coasts were generally very favorable for ice drift south and for ice 

 survival during December, January and February. As a result many 

 bergs had drifted to a position about 200 miles north of the Grand 

 Banks by 1 March. Three early bergs had already drifted onto the 

 Grand Banks. There were an estimated 130 bergs south of Belle Isle, 

 360 from 52° N.-56° N., and 410 from 56° N. to Cape Chidley, 

 Labrador, for a total of about 900 bergs south of Cape Chidley. 



The very favorable weather conditions for ice survival and drift 

 south persisted into March and April along northern Newfoundland 

 and Labrador (average strong cold northwesterly air flow) with the 

 result that considerable ice was rapidly transported toward and onto 

 the Grand Banks during this period. The prevailing winds drove 

 the first wave of bergs out of the main branch of the Labrador Cur- 

 rent toward and close along the east coast of Newfoundland with many 

 permanently removed as a threat to the major shipping lanes. While 

 the threat to shipping had been greatly relieved, an estimated 88 bergs 

 drifted south of 48° N. during March creating the third heaviest 

 March berg month on record (using 48° N. as a yardstick). 



April was characterized by two distinct weather patterns with winds 

 averaging strong west by south over the northern Grand Banks for 



