south to 48N after winds became favorable in 

 later April. Gradient 3 shows that winds were 

 generally unfavorable for iceberg drift along the 

 eastern slopes of the Grand Banks until early 

 May when conditions became neutral and re- 

 mained so through early June when they again 

 became unfavorable. Pressure gradient 4 shows 

 that winds would have tended to hold icebergs in 

 along the Newfoundland coast until early May. 

 As the iceberg supply on the northern Grand 

 Banks became adequate in early June there ap- 

 pears to have been a tendency for winds, as meas- 

 ured on gradient 4, to carry them eastward out 

 of the Labrador Current. 



Winter and spring air temperatures along the 

 Baffin Island, Labrador and Newfoundland 

 coasts were generally warmer than normal, as 

 can be seen in figure 21. The locations of the sta- 

 tions given on figure 21 are shown on figure 19. 

 A frost degree-day, as used in figure 21, is defined 

 as one day at a temperature of one fahrenheit 

 degree below 32°. Thus one day at 20 °F would 

 be 12 frost degree-days. Similarly a melting 

 degree-day is defined as a day at a temperature 

 of one Fahrenheit degree above 32°. Actually 

 figure 21 was calculated on the basis of the aver- 

 age monthly temperature and multiplied by the 

 number of days in the month rather than on the 



basis of the average daily temperature for each 

 day. 



The only station which was not below normal 

 in frost degree-day accumulations was Resolution 

 Island. Along the Labrador and Newfoundland 

 coasts it appears that the reason for the low frost 

 degree-day accumulations was a late winter. Once 

 temperatures dropped below freezing monthly 

 frost degree-days were usually only slightly lower 

 than normal. An exception to this was St. Johns 

 where the frost degree-days in February and 

 March were much below normal. The effect of 

 these below normal frost degree-days would be 

 to inhibit the formation of sea ice, which in turn 

 would hasten the deterioration of icebergs since 

 sea ice generally serves to protect icebergs from 

 the eroding influence of wave action. The below 

 normal extent of sea ice has already been men- 

 tioned in the section on ice conditions during 

 1970. 



Melting degree-days at St. Johns in May and 

 June were above normal. This would tend to 

 cause increased melting of icebergs in the area. 



To summarize, it appears that in spite of a 

 large supply of icebergs, a heavy 1970 iceberg 

 season failed to materialize because wind, air 

 temperature, sea surface temperature, and sea ice 

 conditions were not favorable for the transport 

 of icebergs south of 48 °N. 



