Environmental Conditions 



1987 Season 



The wind direction along 

 the Labrador and Newfoundland 

 coasts can affect the iceberg 

 severity of each year. The 

 mean wind flow can influence 

 iceberg drift. Dependent upon 

 wind intensity and duration, 

 icebergs can be accelerated 

 along or driven out of the main 

 flow of the Labrador Current. 

 Departure from the Labrador 

 Current normally slows their 

 southerly drift, and in many 

 cases speeds up their rate of 

 deterioration. 



The wind direction and 

 air temperature affect the 

 iceberg severity of each year in 

 an indirect way by influencing 

 the extent of sea ice. Sea ice 

 protects the icebergs from 

 wave action, the major agent of 

 iceberg deterioration. If the 

 air temperature and wind 

 direction are favorable for the 

 sea ice to extend to the south 

 and over the Grand Banks of 

 Newfoundland, the icebergs 

 will be protected longer as they 

 drift south. When the sea ice 

 retreats in the spring, large 

 numbers of icebergs will be 

 left behind on the Grand Banks. 

 Also, if the time of sea ice 

 retreat is delayed by below 

 normal air temperatures, the 

 icebergs will be protected 

 longer, and a longer than 

 normal ice season can usually 

 be expected. The opposite is 

 true if the southerly sea ice 

 extent is minimal, or if above 

 normal temperatures cause an 

 early retreat of sea ice from 

 the Grand Banks. 



The following discussion 

 summarizes the environmental 

 conditions along the Labrador 

 and Newfoundland coasts for the 

 1987 ice year. The Gander 

 Airport Weather Office pro- 

 vided the data for Table 6. 



January: The mean pressure 

 distribution in Figure 3 shows 

 the Icelandic Low was south- 

 west of its mean position, with 

 stronger than normal pressure 

 gradients surrounding it. The 

 resulting stronger northerly 

 flow brought more Polar Con- 

 tinental air to Labrador causing 

 colder, drier than normal 

 conditions, and more Polar 

 Maritime air to Newfoundland 

 causing colder, wetter condi- 

 tions (Table 6). The Grand 

 Banks conditions were proba- 

 bly similar to the Newfound- 

 land conditions, colder, wetter 

 than normal. 



February: The Icelandic Low 

 remained intense in February 

 and shifted farther to the 

 southwest, bringing a north- 

 easterly flow to Labrador and 

 Newfoundland (Figure 4). The 

 conditions in Labrador were 

 warmer and wetter than nor- 

 mal, while the temperatures on 

 Newfoundland were about 

 normal with above normal 

 precipitation (Table 6). These 

 conditions were caused by the 

 northeasterly flow bringing in 

 large amounts of Polar Mari- 

 time air to the region. This 

 maritime air would have a 

 warmer temperature and more 

 moisture than the continental 



air usually influencing 

 Labrador's weather. 



March: The Icelandic Low 

 returned to its usual position 

 and nearly normal intensity for 

 March (Figure 5). In addition 

 to the Icelandic Low, a low 

 pressure trough extended from 

 the Grand Banks south. Condi- 

 tions in Nain and Gander re- 

 turned to nearly normal while 

 Goose Bay was drier than 

 normal and St. John's was 

 colder and wetter than normal 

 (Table 6). The northwesterly 

 flow brought dry polar air to 

 Goose Bay instead of the mari- 

 time air it is usually influ- 

 enced by. The low pressure 

 trough off the Grand Banks 

 brought moisture to St. John's 

 from the south. The conditions 

 on the Grand Banks were 

 probably similar to those at St. 

 John's, colder and wetter than 

 normal. 



April: The Icelandic Low was 

 more intense than normal for 

 April, and the position of the 

 Bermuda High was more to the 

 northwest than normal (Figure 

 6). This pressure distribution 

 brought a southwesterly flow to 

 Newfoundland, and a westerly 

 flow to Labrador. The condi- 

 tions at Newfoundland were 

 warmer and wetter than nor- 

 mal, while the conditions on 

 Labrador were warmer and 

 drier than normal (Table 6). 

 These conditions were caused 

 by the southwesterly flow 

 bringing warmer, moister, 

 maritime air to Newfoundland, 



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