To determine and assign numerical values to the existing wind 

 conditions, surface pressure gradients (differences in atmospheric 

 pressure along a geographically orientated line) may be used. Four 

 such gradients are labeled in figure 28. Gradients 1 and 2 measure 

 the winds which are important in setting up the drift for transporting 

 icebergs to the general area of the waters off northeast Newfoundland. 

 Gradient 3 measures the component which assists or impedes icebergs as 

 they drift along the eastern slope of the Grand Banks. Gradient 4 is 

 a measure of the influence of the generally westerly winds along the 

 northern slopes of the Grand Banks. This is important in drifting the 

 icebergs away from the northeast Newfoundland coast and into the 

 Labrador Current. If, however, they are too strong (or persistent) 

 when the icebergs reach the northeast corner of the Grand Banks they 

 may be carried eastward out of the Labrador Current and into warmer 

 waters which drift generally northeastward (as happened this year) . 



Referring now to the graphical representations of figure 29, 

 Gradient 2 is significantly above normal while gradient 1 averaged 

 more than twice the normal magnitude of favorable southward-induced 

 iceberg drift. These persistent winds provided a constant iceberg 

 supply to the waters off northeast Newfoundland. Gradient 3 shows an 

 unfavorable drift along the eastern slopes of the Grand Banks while 

 Gradient 4 shows a tendency for iceberg drift eastward out of the 

 Labrador Current, especially during the months of April, May and June. 

 Had either or both pressure Gradients 3 and 4 been closer to normal, 

 hundreds (perhaps even thousands) more icebergs could have drifted 

 south of 48°N. 



December air temperatures along the Baffin Island, Labrador and 

 Newfoundland coasts set a record low. Temperatures continued much 

 colder than normal during the remaining winter and all the spring 

 months as shown in figure 30. Temperatures averaged in excess of 

 7**F below normal. The locations of the stations are shown in figure 

 28. A frost degree day, as used in figure 30, is defined as one day 

 at a temperature of one Fahrenheit degree below 32° (e.g., one day 

 at 20''F would be 12 frost degree days) . Similarly a melting degree 

 day is one day at a temperature of one Fahrenheit degree above 32°. 

 All the stations had a much greater than normal frost degree day 

 accumulation and all but St. John's, Newfoundland had a smaller than 

 normal melting degree day accumulation. Adding these influences 

 together, iceberg deteioration due to both wave action (inhibited due 

 to the large extent of sea ice already discussed in a prior section) 

 and melting was greatly retarded thus extending the Ice Season 

 approximately two months longer than normal. 



18 



