lower in February) than 

 normal. Temperatures were 

 about 2°C below normal, and 

 winds were from the west/ 

 northwest overthe Newfound- 

 land coast. The wind direc- 

 tion and colder temperatures 

 resulted in the sea ice extent 

 being much greater than 

 normal to the south and east 

 during January, February, 

 and March. Figure 8 shows 

 the sea ice extent on 1 2 March 

 1990 compared to the mean 

 sea ice edge. There were 8 

 new bergs south of 48°N in 

 February, the first month 

 with bergs in the IIP area, and 

 1 13 south of 48°N in March. 



The greaterthan normal 

 sea ice conditions during the 

 first part of the ice season 

 protected icebergs from de- 

 terioration longer. Further- 

 more, when the ice edge re- 

 ceded to the north in April 

 (the ice edge receded over 

 500 km between mid-March 

 and mid-April) a large num- 

 ber of icebergs were released 

 farther south than normal. 

 There were 376 new bergs 

 south of 48°N in April. From 

 mid-April to mid-June (Fig- 

 ures 9,10, and 11) the south- 

 ern edge of the sea ice re- 

 mained at about 51 °N, just 

 inside the IIP area, and its 

 extent was still greater than 

 normal. During May, the IIP 

 Limits of All Known Ice ex- 

 tended south of 40°N, the IIP 



southern boundary. This ex- 

 treme southern limit of bergs 

 was probably influenced by 

 the extreme southern extent 

 and late retreat of the sea ice. 

 Furthermore, sea surface 

 temperature (SST) charts 

 show that the North Atlantic 

 Current made a southward 

 meander in the region south 

 of the Grand Banks (approxi- 

 mately 40°N, 50°W) during 

 the latter half of May. This 

 permitted a tongue of the 

 colder (less than 6°C) Labra- 

 dor Current to extend farther 

 south than normal. From 15- 

 25 May, the Labrador Cur- 

 rent, the main mechanism 

 for transporting icebergs 

 southward, extended below 

 39°N before receding to 

 the north. This tongue of 

 colder water undoubtedly 

 was the primary reason for 

 the extreme southern ice- 

 berg extent during May. Eight 

 bergs were predicted to drift 

 south of 40°N during May by 

 HP's computer model, and 

 the southernmost berg 

 sighted during the season 

 was at 38.8°N, 47.3°W on 26 

 May 1990. Because MP's 

 computer model was not 

 able to drift bergs south of 

 40°N, IIP increased aerial 

 reconnaissance of the south- 

 ern Limits of All Known Ice 

 during this period of extreme 

 iceberg extent. IIP also drew 

 larger than standard error 

 circles around the bergs 



south of 40°N and expanded 

 the error circles daily to a 

 maximum of 45 miles from 

 the last sighted or predicted 

 berg position after four days 

 on plot. Figures 1 5 -26 show 

 the IIP Limits of All Known Ice 

 and the sea ice edge for the 

 15th and 30th of each month 

 of the ice season. 



During June the south- 

 ern berg extent began to de- 

 crease, and between 30 May 

 and 15Junethe IIP Limit of All 

 Known Ice receded about 

 500 km to the north. Under 

 the influence of southwest- 

 eriy winds the sea ice finally 

 departed the IIP area in mid- 

 June, and by mid-July there 

 was no sea ice south of 57°N. 



In summary, 1 990 was a 

 heavy ice year in terms of 

 the number of bergs south of 

 48°N and uncommonly severe 

 in terms of the southern ex- 

 tent of bergs. This probably 

 resulted from the greater than 

 normal sea ice extent protect- 

 ing the bergs longer and re- 

 leasing them farther south 

 in MP's area and the anoma- 

 lous Labrador Current flow 

 which transported the bergs 

 to extreme southern extents. 



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