Figure 30. shows Gradients 5 and 6 for both the 1972 (not 

 analyzed last year) and 1973 pre-season periods of September 

 to February and continued through April. It is more than 

 apparent that from the end of November and continuing until 

 the middle of April, 1972 more than twice the average wind 

 gradient provided southerly drift for icebergs from far to 

 the north of Davis Strait. These northern icebergs, previously 

 uncounted in the January pre-season survey, were given an 

 impedous to reach the Grand Banks, a journey not possible 

 under normal environmental conditions. This five month anomaly 

 also extended the iceberg season to the longest on record by 

 providing a constant flow of icebergs out of Baffin Bay. 



Now looking at the 1973 season statistics on the same 

 figure, only two months of excessive positive deviation are 

 noted, preceeded by over a month's negative (southerly winds) 

 gradient. Thus icebergs north of Davis Strait were subjected 

 to normal or above drift rates after the January pre-season 

 flights. Pressure gradient 6, although less negative than 

 normal, indicates that the iceberg transport across Davis 

 Strait must also be taken into account. 



Referring now to the graphical representation of figure 

 31, Gradients 1 and 2 are extremely above normal from the 

 first of December through the first of April. Thus the ice- 

 bergs previously refered to from north of Davis Strait continued 

 their southward drift at excessive rates. Near average 

 gradients in the late spring and early summer months provide 

 for continued iceberg movement south to the vicinity of 48°N, 

 but not at the rate of the previous year. Coupling these with 

 Gradients 3 and 4 as shown, provides for another very long 

 season, equalling the previous year's in length, but falling 

 short of its magnitude. 



As expected from the exceptionally strong northwesterly 

 winds, air temperatures along the Baffin Island, Labrador and 

 Newfoundland coasts were exceptionally low beginning in 

 December which accumulated excessive frost degree days as 

 shown in figure 32. A frost degree day is defined as one day 

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

 day at 25°F would be seven frost degree days). Similarly, a 

 melting degree day is one day at a temperature of one 

 Fahrenheit degree above 32°. The rapid accumulation of 

 melting degree days along the Labrador Coast (Hopedale and 

 Cartwright) correlate with the southerly winds as evidenced 

 by negative gradients (1 and 2, refered to in the previous 

 paragraph) during April and May. Newfoundland melting degree 

 days finally reached a normal accumulation coinciding with 

 the end of the 1973 Ice Season. 



-19- 



