Figure 3.16 Labrador Sea Bathymetry for the SEA Area The

LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Figure 3.16 Labrador Sea Bathymetry for the SEA Area

The Labrador Shelf can be divided into four distinct physiographic regions: coastal embayments; a rough inner shelf; a coast parallel depression referred to as the marginal trough; and a smooth, shallow outer shelf consisting of banks and intervening saddles. These features are presented in Figure 3.17.

3.2.1 Coastal Embayments The Labrador coast in the region of the Makkovik Bank is made up of a series of fjords. The fjords are generally steep-sided with deep U-shaped submarine profiles along the coast north of Cape Harrison, while glacial erosion and low relief prevented fjord development to the south.

Figure 3.17 Location Map of Labrador Shelf Indicating Main Features

Sikumiut Environmental Management Ltd. © 2008 August 2008 106 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT 3.2.1.1 Inner Shelf The inner shelf extends from the coast to approximately the 200 m isobath, with a width of approximately 25 km and a general east-facing slope in the vicinity of Cape Harrison. The topography exhibits jagged erosional features and is topographically complex, having relief and underlying bedrock similar to the adjoining mainland. Local relief features displaying changes in bathymetry are present in areas deeper than 75 m water depth and shoals are common. Soil deposits are generally present in depressions or buried channels. Localized seabed slopes of 30 degrees are not uncommon, and some vertical faces can be expected, particularly at bedrock outcrops. A number of channels have been recorded as part of detailed bathymetric surveys of the Inner Shelf, which may be useful in pipeline routing exercises. Bathymetry obtained from Canadian Hydrographic Survey charts show the presence of Hopedale Run, a 200 m deep channel passing between the islands just north of Cape Harrison (Figure 3.18), bathymetric data obtained during a 2006 multibeam survey by the GSC, also just north of Cape Harrison (GSC 2006) are illustrated in Figure 3.19. Figure 3.18 Hopedale Run Channel passing through Inner Shelf

Source: King, A.D. and Sonnichsen, G., (2008) and Fugro Jacques GeoSurveys Inc. (2007).

3.2.1.2 Marginal Trough The break between the inner and outer shelf is marked by the marginal trough, which reaches depths up to 800 m locally, although is more commonly limited to 300 m. The trough section is asymmetrical, with the east wall being steeper than the west. The axis of this depression occurs at the contact between the erosion-resistant crystaline Precambrian bedrock of the inner shelf and the softer sedimentary sediments of the coastal plain sequence, which underlie the outer shelf. The trough depression is thought to have formed as a result of differential erosion by the advancing pleistocine ice sheet.

Sikumiut Environmental Management Ltd. © 2008 August 2008 108 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT 3.2.1.3 Outer Shelf The outer shelf is topographically subdued, with relatively smooth surfaced, discrete banks. For the most part, it comprises sedimentary rocks of Late Cretaceous to Paleocene age that form a series of banks (<200 m deep), which are separated by east-west trending depressions called saddles, with depths up to 800 m. The Makkovik Bank is generally at water depths of 135 to 150 m, with local shoals of less than 90 m. Water depths generally increase from west to east. Quaternary sediments on the outer shelf are typically less than 100 m thick, but vary from 300 m near Hudson Strait to less than 10 m on Hamilton Bank. The presence of moraines and other glacial features results in local bathymetric relief (mounds or depressions) of up to 10 m, with diameters of several hundred metres.

3.3 Metocean Conditions The design and operation of offshore installations is dependent on good knowledge of meteorological and oceanographic (metocean) conditions to which an installation may be exposed. Of most importance are wind, wave and current conditions at the location of the installation. However, at some locations and for specific types of operations, other factors such as tides, air and sea temperature and visibility are also important. In order to plan a weather-sensitive offshore operation, it is the metocean conditions that may be expected to occur during the course of the operation that are of interest.

3.4 Sea Conditions

3.4.1 Temperature and Salinity Fisheries and Oceans Canada (DFO) maintains a hydrographic database at http://www.mar.dfo- mpo.gc.ca/science/ocean/tsdata.html, which contains seasonal maps of the mean sea surface temperature and salinity, respectively, for the shelf regions off the coast of Newfoundland and Labrador. Temperature and salinity fields are estimated from all available data collected by DFO. The seasonal estimates are made for the 15th of the month during February (winter), May (spring), August (summer) and November (fall). Sea surface temperatures (Figure 3.20) in the Labrador Shelf SEA Area remain relatively cold in the north (typically -2°C to 0°C) throughout the year. South of 55°N temperatures range from approximately 0°C during the winter months to approximately 10°C during summer. Salinity (Figure 3.21) hovers around 30 psu (practical salinity units) inshore and over the banks during spring and summer, and increases to greater than 35 psu at the edge of the Labrador Shelf. During fall and winter, it tends to increase to approximately 33 psu inshore and remains fairly constant at approximately 35 to 36 psu over the edge of the shelf.

Source: DFO 2007a.

Figure 3.21 Seasonal Salinity Plots

Source: DFO 2007a.

3.4.2 Wave Conditions The AES40 wind and wave hindcast has been the standard for wind and wave climatology of the North Atlantic Ocean. This hindcast has been widely used in wind and wave climate and engineering studies for the North Atlantic, particularly for the areas offshore the east coast of Canada. The MSC50 hindcast from the Meteorological Service of Canada, which replaces the AES40, takes advantage of all the inputs of its predecessor, and introduces some important enhancements, particularly for the Canadian east coast offshore regions. These include:

• a finer grid, (0.5 degree) over the entire North Atlantic; • a 0.1 degree grid over the Northwest Atlantic; • shallow water effects in the fine grid area; • better bathymetry and sea ice information;

• increased use of scatterometer wind data and storm track information; and • continuous hindcast wind and wave data spanning 50 years (1954 to 2005). The grid point locations used for this study are shown in Figure 3.22, the coordinates for each location are contained in Table 3.1. Monthly wave statistics for each MSC50 grid point are contained in Tables 3.2 to 3.10. These values are based on 50 years of hindcast data. Plots of monthly mean and maximum wave height are shown in Figure 3.23. Extreme 10-year, 50-year and 100-year significant wave heights are shown in Table 3.11. Figure 3.22 MSC50 Grid Point Locations

Table 3-1 MSC50 Grid Point Locations MSC50 grid point Latitude Longitude 14986 60.0°N 61.0°W 14710 59.0°N 60.0°W 14434 58.0°N 59.0°W 14161 57.0°N 58.0°W 13893 56.0°N 57.0°W 13643 55.0°N 55.0°W 13408 54.0°N 53.0°W 13194 53.0°N 52.0°W 12995 52.0°N 51.0°W

Table 3-2 Grid Point 14986 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 5456 2.42 1.41 9.95 February 2262 2.10 1.30 10.53 March 3469 1.84 1.07 7.23 April 3839 1.55 0.84 5.26 May 5454 1.34 0.67 5.08 June 7677 1.29 0.70 5.92 July 11153 1.20 0.60 4.64 August 12891 1.33 0.67 5.06 September 12480 1.80 0.89 7.86 October 12896 2.29 1.11 8.35 November 11520 2.63 1.32 9.90 December 11160 2.69 1.41 10.57

Table 3-3 Grid Point 14710 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 5704 2.75 1.47 10.03 February 4743 2.24 1.35 11.19 March 5950 2.13 1.14 8.95 April 6236 1.92 0.94 6.54 May 6943 1.49 0.72 5.53 June 8878 1.37 0.70 6.90 July 11403 1.21 0.58 4.34 August 12644 1.32 0.65 4.93 September 12479 1.81 0.87 6.62 October 12896 2.33 1.12 9.36 November 11760 2.73 1.35 11.22 December 11408 2.93 1.44 12.12

Table 3-4 Grid Point 14434 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 8927 2.90 1.55 11.00 February 6334 2.64 1.49 11.67 March 8676 2.40 1.34 11.47 April 8637 2.13 1.09 8.39 May 8679 1.63 0.82 7.27 June 10077 1.46 0.76 8.67 July 11653 1.26 0.63 4.89 August 12645 1.37 0.69 5.64 September 12479 1.88 0.91 7.24 October 12896 2.44 1.20 10.55 November 12480 2.87 1.45 12.23 December 10912 3.23 1.55 11.51

Table 3-5 Grid Point 14161 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 6944 3.13 1.62 11.48 February 5414 2.78 1.52 9.92 March 7439 2.64 1.40 12.39 April 8638 2.20 1.14 9.17 May 8679 1.62 0.84 7.99 June 10317 1.44 0.75 7.80 July 11900 1.20 0.60 4.78 August 12647 1.33 0.66 5.67 September 12479 1.87 0.91 8.53 October 12896 2.44 1.20 10.55 November 12480 2.88 1.42 11.70 December 10912 3.33 1.57 11.34

Table 3-6 Grid Point 13893 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 6448 3.22 1.58 11.87 February 4511 2.82 1.54 10.08 March 6695 2.65 1.42 12.48 April 7678 2.22 1.16 9.71 May 8926 1.62 0.86 7.18 June 10556 1.44 0.77 7.91 July 11653 1.21 0.59 4.62 August 12644 1.33 0.65 5.53 September 12479 1.88 0.92 9.14 October 12896 2.45 1.19 11.16 November 12480 2.88 1.40 11.77 December 10912 3.32 1.55 11.34

Table 3-7 Grid Point 13643 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 8183 3.21 1.59 12.61 February 3167 3.13 1.61 11.10 March 6199 2.70 1.35 11.35 April 6479 2.35 1.19 10.35 May 8926 1.74 0.89 8.52 June 9359 1.53 0.75 6.99 July 12397 1.26 0.53 4.52 August 12895 1.39 0.61 5.67 September 12480 2.00 0.94 9.98 October 12896 2.56 1.18 10.50 November 12480 3.00 1.35 11.61 December 11160 3.38 1.46 10.65

Table 3-8 Grid Point 13408 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 10416 3.55 1.56 12.52 February 5880 3.36 1.48 11.51 March 8924 3.02 1.48 11.88 April 9116 2.52 1.24 10.51 May 10909 2.00 0.93 9.37 June 11756 1.66 0.77 6.34 July 12648 1.39 0.57 4.99 August 12895 1.54 0.65 6.02 September 12480 2.20 1.01 10.84 October 12896 2.78 1.23 10.64 November 12480 3.25 1.41 12.59 December 12896 3.67 1.53 11.13

Table 3-9 Grid Point 13194 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 11904 3.69 1.53 12.32 February 7456 3.34 1.46 11.10 March 9916 3.03 1.46 11.32 April 10317 2.57 1.26 9.84 May 12151 2.02 0.92 9.32 June 12478 1.69 0.76 5.69 July 12648 1.44 0.57 5.25 August 12896 1.59 0.65 6.14 September 12480 2.25 1.02 10.68 October 12896 2.83 1.21 10.57 November 12480 3.31 1.40 12.48 December 12896 3.76 1.54 10.74

Table 3-10 Grid Point 12995 Monthly Mean, Standard Deviation and Maximum Wave Height Mean Significant Max Significant Number of Standard Deviation Month Wave Height Wave Height Hindcasts (m) (m) (m) January 12152 3.96 1.56 12.07 February 8584 3.46 1.55 11.63 March 9423 3.23 1.49 11.30 April 9356 2.70 1.28 10.19 May 12645 2.11 0.96 8.98 June 12240 1.79 0.76 6.23 July 12896 1.53 0.59 6.00 August 12896 1.68 0.67 6.86 September 12480 2.34 1.06 10.83 October 12896 2.93 1.24 11.08 November 12480 3.41 1.43 11.44 December 12896 3.90 1.61 11.53

Figure 3.23 Mean and Maximum Monthly Significant Wave Height by Grid Point

Table 3-11 Extreme 10-Year, 50-Year and 100-Year Significant Wave Heights 10-Year Maximum 50-Year Maximum 100-Year Maximum Grid Point (m) (m) (m) 14986 9.63 10.81 11.26 14710 10.55 12.13 12.72 14434 11.07 12.35 12.82 14161 11.15 12.49 12.99 13893 11.14 12.51 13.01 13643 11.19 12.56 13.07 13408 11.66 12.78 13.19 13194 11.72 12.77 13.16 12995 11.41 12.11 12.36

3.4.3 Wind Speed The MSC50 hindcast was used to extract monthly wind parameters for each of the grid point locations shown in Figure 3.22. Monthly statistics are contained in Tables 3.12 to 3.20 plots of monthly mean and maximum wind speeds for all grid point locations are shown in Figure 3.24. Extreme 10-year, 50- year and 100-year wind speeds are shown in Table 3.21. Table 3-12 Grid Point 14986 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 8.72 4.12 23.81 February 11752 7.65 3.81 23.63 March 12896 7.28 3.62 22.99 April 12480 6.63 3.23 21.59 May 12896 5.84 2.96 18.98 June 12480 5.35 2.93 19.77 July 12896 4.97 2.80 16.56 August 12896 5.61 2.97 18.57 September 12480 7.07 3.34 21.23 October 12896 8.61 3.61 23.83 November 12480 9.54 3.99 24.83 December 12896 9.88 4.07 27.32

Table 3-13 Grid Point 14710 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 9.72 4.13 24.44 February 11752 8.57 3.83 24.61 March 12896 8.26 3.71 23.76 April 12480 7.31 3.30 21.45 May 12896 6.11 2.97 20.05 June 12480 5.40 2.80 18.22 July 12896 4.84 2.62 16.46 August 12896 5.44 2.80 17.71 September 12480 6.98 3.20 19.92 October 12896 8.57 3.52 23.57 November 12480 9.55 3.87 27.26 December 12896 10.33 4.04 29.16

Table 3-14 Grid Point 14434 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 10.76 4.52 28.29 February 11752 9.67 4.23 27.63 March 12896 9.25 4.17 25.73 April 12480 8.03 3.74 22.91 May 12896 6.51 3.39 21.83 June 12480 5.73 3.17 20.84 July 12896 5.05 2.99 18.06 August 12896 5.65 3.13 19.38 September 12480 7.26 3.53 22.98 October 12896 8.89 3.85 25.17 November 12480 9.88 4.16 28.69 December 12896 10.93 4.39 29.32

Sikumiut Environmental Management Ltd. © 2008 August 2008 117 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Table 3-15 Grid Point 14161 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 10.33 4.21 27.71 February 11752 9.26 3.93 27.74 March 12896 8.92 3.93 25.04 April 12480 7.70 3.55 22.57 May 12896 6.11 3.22 22.54 June 12480 5.36 2.94 20.15 July 12896 4.72 2.68 16.17 August 12896 5.32 2.84 17.53 September 12480 6.96 3.30 24.15 October 12896 8.59 3.60 25.88 November 12480 9.59 3.86 26.58 December 12896 10.58 4.07 29.15

Table 3-16 Grid Point 13893 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 10.53 4.29 28.23 February 11752 9.61 4.02 27.14 March 12896 9.11 4.01 26.61 April 12480 7.77 3.70 23.66 May 12896 6.18 3.37 21.59 June 12480 5.42 3.13 19.85 July 12896 4.77 2.82 16.56 August 12896 5.38 2.98 18.01 September 12480 7.09 3.45 24.91 October 12896 8.68 3.71 25.53 November 12480 9.67 3.92 26.38 December 12896 10.60 4.13 27.98

Table 3-17 Grid Point 13643 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 10.32 4.06 29.40 February 11752 9.41 3.78 27.64 March 12896 8.91 3.71 24.51 April 12480 7.65 3.46 22.29 May 12896 6.22 3.16 21.58 June 12480 5.45 2.89 19.03 July 12896 4.79 2.53 16.30 August 12896 5.36 2.73 17.35 September 12480 7.14 3.28 24.17 October 12896 8.60 3.53 23.86 November 12480 9.62 3.70 28.25 December 12896 10.46 3.88 27.09

Table 3-18 Grid Point 13408 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 11.05 4.28 28.29 February 11752 10.38 4.06 27.79 March 12896 9.74 4.02 25.18 April 12480 8.37 3.79 22.83 May 12896 6.91 3.39 21.61 June 12480 6.07 3.16 19.02 July 12896 5.33 2.82 16.40 August 12896 5.85 3.01 19.47 September 12480 7.68 3.54 25.28 October 12896 9.09 3.78 24.69 November 12480 10.10 3.96 27.04 December 12896 10.93 4.14 27.08

Table 3-19 Grid Point 13194 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 11.28 4.09 26.18 February 11752 10.48 3.97 26.65 March 12896 9.81 3.90 28.64 April 12480 8.58 3.74 23.43 May 12896 7.11 3.26 21.60 June 12480 6.25 2.96 19.02 July 12896 5.60 2.63 19.65 August 12896 6.14 2.82 18.77 September 12480 7.83 3.44 25.71 October 12896 9.20 3.67 24.61 November 12480 10.25 3.85 26.49 December 12896 11.09 4.06 26.23

Table 3-20 Grid Point 12995 Monthly Mean, Standard Deviation and Maximum Wind Speed Number of Mean Wind Speed Standard Deviation Max Wind Speed Month Hindcasts (m/s) (m/s) (m/s) January 12896 11.74 4.38 28.19 February 11752 11.14 4.32 28.80 March 12896 10.33 4.21 29.32 April 12480 8.98 4.05 23.36 May 12896 7.46 3.52 22.45 June 12480 6.56 3.20 20.71 July 12896 5.97 2.87 17.99 August 12896 6.48 3.03 20.05 September 12480 8.09 3.68 25.16 October 12896 9.47 3.93 25.65 November 12480 10.53 4.13 26.81 December 12896 11.39 4.37 28.99

Sikumiut Environmental Management Ltd. © 2008 August 2008 119 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Table 3-21 10-Year, 50-Year and 100-Year Extreme Wind Speeds 10 Year Maximum 50 Year Maximum 100 Year Maximum Grid Point (m/s) (m/s) (m/s) 14986 25.40 27.33 28.04 14710 26.52 28.98 29.88 14434 27.42 29.29 29.98 14161 26.99 29.14 29.93 13893 26.80 28.59 29.23 13643 26.98 29.44 30.34 13408 26.90 28.59 29.20 13194 26.79 28.61 29.28 12995 28.22 30.27 31.02

Figure 3.24 Mean and Maximum Monthly Wind Speed by MSC50 Grid Point

3.4.4 Current As illustrated in Figure 3.25 (a general illustration of the Labrador Current), the Labrador Current, originating in the Davis Strait, is a combination of the West Greenland Current, the Baffin Island Current and inflow from Hudson Bay. It flows along the Labrador coast and consists of two major streams, the inshore and offshore stream. The inshore stream, consisting of water from Hudson Strait and the Baffin Current, flows along the coast and in the Marginal Trough, located inside the banks. The offshore stream consists of water from the West Greenland current and flows along the outer edge of the banks and over the continental slope. Hydrographic observations in the Labrador Sea from the 1930s to the 1990s reveal large annual and decadal variations in water mass properties. In the late 1960s - early 1970s, the intermediate and deep waters of the Labrador Sea were at their warmest and saltiest since the 1930s. It took only two decades for all the waters to reach the lowest ever observed temperature and salinity of the entire water column. Figure 3.25 General Ocean Circulation

The Labrador Sea has exhibited significant variations in its temperature and salinity over the past 45 years. These changes have important implications for both the global climate system and the regional climate and marine ecosystems. Hydrographic observations from the 1930s to the 1990s reveal large annual and decadal variations in water mass properties. This variability has been linked to the larger- scale variability of the North Atlantic climate.

Sikumiut Environmental Management Ltd. © 2008 August 2008 121 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Surveys conducted by the Ocean Sciences Division, DFO Maritimes Region during 1990 to 2002 monitored a period of intense deep convection and abundant Labrador Sea water formation, followed by a period of restratification and the present-day trend to warmer and more saline conditions. Even warmer and saltier conditions were observed in the mid-1960s when the intermediate and deep waters of the Labrador Sea were the warmest and saltiest ever recorded. It took only two decades for the entire water column to reach the lowest ever observed temperature and salinity. The cold winter of 1971 to 1972 gave rise to record-high sea–air heat fluxes in the Labrador Sea. While the upper 2000 m of the Labrador Sea were the coldest and freshest on record in 1994, these waters have warmed and become more saline and are now approaching the conditions observed in the early 1960s. Only the future will show if the temperature and salinity of the upper levels of the Labrador Sea will reach the values seen in the mid-1960s. The historical record suggests that natural variability will provide yet another period of cold winters to renew deep convection and reset the system. The balances controlling Labrador Sea properties would likely change with any shift in climatic conditions such as global warming. The presence of the banks between the two main streams of the Labrador Current tends to limit mixing of the streams so that they maintain their water properties along the length of the coast. Mixing of the streams occurs through the saddles, which are oriented approximately perpendicular to the coast. The currents on the banks between the two streams are weak and much more variable. Mean velocities are greatest along the slope and in the Marginal Trough, while the maximum speeds are greatest along the slope and in the Cartwright Saddle. Figure 3.26 illustrates the mean ocean current field modeled with the new Canadian East Coast Ocean Model (CECOM) by the Bedford Institute of Oceanography (BIO). The implementation of CECOM provides an improvement over the previous Labrador Sea Model. The model physics is similar to the previous Labrador Sea model, but an enhanced coordinate system, model domain and larger coverage (including Baffin Bay, Labrador Sea, Scotian Shelf and Gulf of St. Lawrence) have improved its functionality. The model has been implemented in a forecast system run daily at BIO. The most comprehensive physical study of currents offshore Labrador was contracted by Petro-Canada during the summer of 1980. Prior to the 1980 Physical Oceanography Study offshore Labrador, currents were measured by various researchers. A summary of these measurements as compiled for the offshore Labrador Initial Environmental Assessments by Petro-Canada are presented in Table 3.22. The approximate location of each mooring with respect to the major bathymetric features is indicated by B, S, or T for on the banks, on the continental shelf, or in the Marginal Trough, respectively. For each current meter record, the maximum-recorded speed, mean speed, mean velocity and current steadiness are listed. The steadiness parameter, as defined by Ramster et al. (1978), is the ratio of the magnitude of the mean velocity to the mean speed, multiplied by 100 and is a measure of how representative the mean velocity is of the actual flow. Ramster et al. (1978) suggest that the mean velocity ceases to represent the actual flow as the steadiness decreases to less than 70 percent.

Source: Yao et al 2000.

Sikumiut Environmental Management Ltd. © 2008 August 2008 123 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT Table 3-22 Moored Current Meter Measurements on the Labrador Shelf and Slope prior to 1980 Water Meter Mean Mean Velocity Banks (B) Duration Max Speed Steadiness Location Depth Depth Dates Speed Magnitude Direction Source Slopes (S) (Days) (cm/sec) (%) (m) (m) (cm/sec) (cm/sec) (°T) Jul-Aug 53º30'N B 217 37 14 n/a 19 n/a (1) 1970 81 n/a 14 n/a 54º29'W 124 n/a 19 n/a 55º39'N B 160 34 Aug-79 9 34 14 n/a 78 40 14 2.7 218 19 57º42'W (5) 130 40 12 2.6 179 22 Mar-Apr 56º49'N S 3000 260 27 45 20 8.7 13 44 (3) 1976 Mar-Apr 56º33'N S 2600 160 27 75 35 15.2 188 43 (3) 1976 56º22'W 2500 30 25 12.1 201 48 Oct 1977 - 57º25'N S 600 100 95 94 39 35.3 157 91 (4) Jan 1978 250 60 17 13.8 154 79 59º09'W 500 44 13 10.5 147 83 Oct 1977 – 57º35'N S 1320 100 95 89 25 22.3 109 89 (4) Jan 1978 59º02'W 500 37 13 11.6 157 89 Jan-Jul 57º35'N S 1306 1200 166 31 6 3.6 152 55 (4) 1978 Jan-Jul 57º18'N S 600 100 166 86 36 33.5 157 94 (4) 1978 59º10'W 500 500 58 11 9 173 79 58º30'N B 200 13 Aug-72 14 79 40 13.7 193 34 (2) 62º02'W 166 27 20 8 252 40 58º37'N B 180 13 Aug-72 14 38 20 4.1 205 21 (2) 62º10'W 136 37 15 6.3 200 42 58º28'N B 200 13 Aug-72 14 75 30 9.2 200 31 (2) 61º57'W 155 24 15 4.6 183 31 Aug-Oct 58º52'N B 192 188 40 30 12 6.6 251 55 (6) 1978 Sources (1) Scobie (1972). (2) Holden (1973). (3) Allen and Huntley (1977). (4) Lazier (1979a). (5) NORDCO (1979). (6) MacLaren Marex (1980b).

Sikumiut Environmental Management Ltd. © 2008 August 2008 124 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT The data prior to 1980 are distributed irregularly in space and time. The measurements on the continental slope were made mainly during the winter season, and the banks during the summer season. The current information in Table 3.23 indicates that the net flows are stronger over the steepest portion of the continental slope than over the continental shelf or locations further offshore. While the magnitude of the vector mean currents are much less on the continental shelf than those measured on the slope, the current speeds on the shelf can still be strong. The maximum current speed on the slope was measured as 0.94 m/s at a depth of 100 m, and the maximum speed on the shelf was measured as 0.79 m/s at a depth of 13 m. Table 3-23 Moored Current Meter Measurements from Petro-Canada’s 1980 Summer Program, July to October 1980, Average 70 Days Duration Banks (B) Mean Mean Velocity Water Meter Depth Max Speed Location Slopes (S) Speed Velocity Direction Depth (m) (m) (cm/sec) Trough (T) (cm/sec) (cm/sec) (°T) 54º10'N T 212 52 44 14.2 11.6 164 55º44'W 203 23 8.0 4.2 164 54º25'N B 152 53 37 10.8 1.6 226 55º15'W 143 30 8.0 3.3 166 54º30'N B 220 153 38 9.6 5.4 147 54º44'W 171 38 9.2 4.7 141 54º37'N T 523 58 53 16.3 12.6 150 56º08'W 156 42 12.1 9.1 140 54º51'N B 278 30 98 24.1 6.8 110 58 74 20.6 6.0 111 55º48'W (saddle) 158 33 12.3 2.4 68 269 29 9.5 3.0 327 55º11'N S 326 62 83 35.1 - - 159 58 19.1 17.6 111 55º16'W 277 41 11.8 9.4 121 55º15'N T 274 64 45.9 11.4 6.9 127 162 40.1 8.6 2.8 112 58º06'W 265 20.5 3.1 1.4 233 55º35'N B 154 25 77.4 17.4 5.6 141 55 47.4 14.6 4.5 139 57º47'W 145 33.4 11.0 5.5 121 56º03'N S 706 102 52.8 17.8 16.1 172 202 45.2 13.8 12.2 175 57º24'W 656 28.8 5.3 3.0 186 57º32'N B 165 56 34.4 10.7 4.9 154 60º28'W 156 24.3 7.5 1.8 145 58º53'N B 179 62 46.7 14.0 5.4 261 62º10'W 170 34.0 12.0 5.4 253 The 1980 Physical Oceanographic Program carried out by NORDCO Limited for Petro-Canada collected current data during the summer season in four main regions: on the banks; on the continental slope; in the Marginal Trough; and in the Cartwright Saddle. Moorings were placed in 11 locations. Three moorings were placed along each of three transects perpendicular to the coast. These were situated across Hamilton Bank, through Cartwright Saddle and across Makkovik Bank. Moorings were also placed on the Nain Bank and Saglek Bank, near the drilling sites. The positions of the moorings are shown in Figure 3.27. A summary of the data is presented in Table 3.23. The mean speeds were greatest along the slope and in the Marginal Trough, while the maximum speed was greatest along the slope and in the Cartwright Saddle. The maximum speed was 0.98 m/s in the Cartwright Saddle at a depth of 30 m.

Ocean current data was obtained online from the Ocean Data Inventory (ODI). The ODI database is an inventory of all of the oceanographic time series data held by the Ocean Science Division at the Bedford Institute of Oceanography (Gregory, 2004). The database includes approximately 5800 current meter and acoustic doppler time series, 4500 coastal temperature time series from thermographs, as well as a small number (200) of tide gauges. A total of 157 data records were extracted from the ODI database. Each record contains the date, location and depth of the current meter, maximum speed, mean speed, and mean direction. The current records were divided into three categories, near surface, mid depth, and near bottom, depending on the depth of the meter. Figure 3.27 shows the location of the current meters along with current vectors indicating the magnitude and direction of the mean values. The near surface currents are the strongest, with the current magnitude decreasing with depth. On the slope and in the Marginal Trough, the mean flow was along the bathymetric contours. On the banks, the mean flow was low and followed the general southeasterly flow of the adjoining regions, with the exception of Saglek Bank, where the mean flow was directed towards the coastline.

Sikumiut Environmental Management Ltd. © 2008 August 2008 126 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT 3.4.5 Tides Fissel and Lemon (1982) carried out a tidal analysis of the data. The largest tidal variations occurred at

semi-diurnal frequencies. The semi-diurnal constituents (M2 and S2) are shown in Table 3.24. For the M2 constituents, the largest amplitude occurred on the Saglek Bank at station 10-1, where M2 was 0.13 m/s at 62 m depth. In comparison with the semi-diurnal tidal currents, the amplitude of the diurnal flows was generally low. At all locations excluding the Makkovik Bank and Nain Bank, the amplitude of

the largest diurnal constituent (K1) ranged from 0.003 to 0.03 m/s. On Makkovik Bank, the K1 constituent ranged from 0.04 to 0.06 m/s, depending on depth. The amplitude of the diurnal constituent

(O1) was nearly as large, ranging from 0.04 to 0.06 m/s. On Nain Bank, the K1 constituent ranged from 0.031 to 0.025 m/s and the O1 constituent from 0.03 to 0.02 m/s.

Table 3-24 Tidal Constituents M2 and S2 Offshore Labrador M S Depth 2 2 Major Minor Inc. Major Minor Inc. Station Latitude Longitude (m) (cm/s) (cm/s) (°) (cm/s) (cm/s) (°) 4-1 54º 10.0' 55º 44.0' 52 3.8 -0.5 144 1.0 -0.3 152 4-1 54º 10.0' 55º 44.0' 203 5.2 -0.8 148 1.4 -0.2 156 4-2 54º 25.2' 55º 15.9' 53 7.4 -3.8 160 3.1 -2.1 169 4-2 54º 25.2' 55º 15.9' 143 5.3 -1.2 158 1.8 -0.7 174 4-3 54º 39.1' 54º 44.0' 54 2.3 -1.4 150 0.8 -0.2 166 4-3 54º 39.1' 54º 44.0' 153 5.7 -2.7 142 2.1 -1.3 150 4-3 54º 39.1' 54º 44.0' 171 5.9 -2.9 144 2.3 -1.4 151 5-1 54º 37.4' 56º 7.7' 58 3.6 -0.8 5 0.9 -0.2 12 5-1 54º 37.4' 56º 7.7' 156 3.0 -0.2 10 1.1 -0.5 20 5-2 54º 51.7' 55º 47.2' 30 1.9 0.8 174 1.9 0.8 174 5-2 54º 51.4' 55º 47.9' 58 2.2 0.6 155 0.8 -0.0 168 5-2 54º 51. 4' 55º 47.9' 158 2.8 0.2 151 1.4 -0.4 166 5-2 54º 51. 4' 55º 47.9' 269 2.6 0.3 145 1.1 -0.2 177 5-3 55º 11.0' 55º 16.1' 159 2.8 0.0 152 1.5 -0.1 16 5-3 55º 11.0' 55º 16.1' 277 3.4 -0.8 171 1.6 -0.9 166 7-1 55º 15.0' 58º 5.9' 64 4.5 -1.8 2 1.8 -0.7 9 7-1 55º 15.0' 58º 5.9' 162 4.4 -1.8 171 1.9 -0.9 166 7-2 55º 36.6' 57º 46.7' 25 10.0 -7.2 1 2.5 -1.5 175 7-2 55º 36.5' 57º 47.4' 55 7.3 -5.3 9 3.0 -2.1 0 7-2 55º 36.5' 57º 47.4' 145 4.5 -2.1 163 4.5 -2.1 163 7-3 56º 2.5' 57º 24.2' 102 6.0 -4.3 154 1.8 -1.6 11 7-3 56º 2.5' 57º 24.2' 202 4.1 -2.9 174 1.6 -1.1 45 7-3 56º 2.5' 57º 24.2' 656 1.5 -0.4 133 0.3 -0.2 154 9-1 57º 32.3' 60º 28.3' 56 3.9 -2.8 105 1.4 -1.1 73 9-1 57º 32.3' 60º 28.3' 156 1.9 -1.1 101 1.9 -1.1 101 10-1 58º 53.3' 62º 10.3' 62 13.4 -4.1 140 4.4 -1.2 135 10-1 58º 53.3' 62º 10.3' 170 11.5 -0.4 110 3.6 0.2 108 With the exception of tides, the major part of the temporal variability of the currents occurred at periods greater than two days. Over the banks, relatively more activity occurs at periods of four to seven days. Over the Marginal Trough and Cartwright Saddle, the peak periods range from 7 to 14 days and on the slope, the currents are dominated by fluctuations in excess of seven days. The currents offshore Labrador is dominated by low frequency oscillations. Fissel and Lemon (1982) found that despite the general similarity of the flow within each regime, cross-spectral analysis between horizontally separated pairs of current records did not reveal statistically significant coherences beyond those that would be expected to arise at random. Much of the spatial variability is linked to bathymetry,

Sikumiut Environmental Management Ltd. © 2008 August 2008 127 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT while the temporal variability may be linked to meteorological forcing as suggested by the period of the oscillations.

3.5 Atmospheric Conditions Raw mean, minimum and maximum daily temperature data were extracted from the Canadian Daily Climate Database for nine weather stations (Figure 3.28) located along the Labrador coast within the SEA Area. The Marine Climatological Atlas-Canadian East Coast (AES 1985) was used to extract monthly wind-chill and visibility statistics for the two cross hatched sub-regions and one offshore weather station (OWS), shown in Figure 3.29.

3.5.1 Air Temperature The temperature data for the various stations are summarized in Tables 3.25 to 3.33. It should be noted that these are land-based stations and temperatures offshore are expected to be less severe. Since the observations are automated hourly readings, it is highly unlikely that the actual maximum and minimum temperatures are reported; as these values would not often occur exactly at the time, the observations were taken. The data given in this report are the minimum and maximum values of the hourly entries. Record length varies from station to station; the number of monthly observations for each station is noted in the tables. Plots of monthly mean, minimum and maximum temperatures for each station are shown in Figure 3.30. Figure 3.28 Location of Weather Stations in SEA Area

Figure 3.29 Location of Sub-regions and Offshore Weather Station (OWS Bravo) Used for Visibility and Wind-chill Characteristics in the SEA Area

Source: after AES 1985.

Table 3-25 Monthly Air Temperatures for Saglek (1955 to 1958) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St. Dev. (°C) Min (°C) Max (°C) January -15.08 9.05 -35.60 4.40 124 February -13.82 7.86 -32.20 5.00 111 March -10.29 5.91 -31.70 3.90 124 April -6.87 4.88 -26.10 7.80 120 May -1.09 3.42 -13.90 9.40 124 June 3.91 2.82 -3.30 23.90 120 July 8.13 3.78 0.60 26.10 93 August 7.88 3.18 0.60 22.80 93 September 5.35 3.46 -3.90 22.80 81 October 1.89 3.16 -7.20 13.90 89 November -3.39 4.71 -19.40 11.10 90 December -9.73 6.66 -25.00 2.20 93

Table 3-26 Monthly Air Temperatures for Hebron (1947 to 1957) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -19.11 6.59 -37.80 1.70 189 February -17.21 7.10 -31.70 7.20 171 March -10.89 6.01 -30.00 6.70 201 April -7.10 5.57 -26.10 10.00 217 May 0.27 3.42 -14.40 26.70 239 June 5.25 3.87 -11.10 28.90 177 July 9.40 3.72 -2.20 37.80 187 August 9.81 3.01 -1.70 22.80 170 September 6.76 3.68 -3.30 22.80 153 October 1.77 3.11 -10.00 15.60 171 November -4.41 3.97 -18.30 8.90 157 December -9.90 5.95 -29.40 5.60 173

Table 3-27 Monthly Air Temperatures for Nutak (1948 to 1953) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -19.24 5.78 -32.80 -1.10 180 February -19.06 6.77 -32.80 5.00 173 March -13.01 6.43 -31.70 6.10 119 April -7.43 5.13 -25.00 7.20 107 May 0.10 3.64 -15.60 26.70 124 June 5.40 3.67 -3.90 28.30 109 July 9.73 2.87 0.60 26.10 113 August 10.69 2.94 0.60 28.30 84 September 6.13 2.87 -2.20 22.20 86 October -0.10 4.85 -18.90 14.40 72 November -6.33 4.50 -24.40 6.70 135 December -11.88 7.09 -30.00 6.10 155

Table 3-28 Monthly Air Temperatures for Nain (1926 to 2003) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -18.75 7.05 -42.50 15.70 1273 February -17.80 7.58 -38.30 7.60 1180 March -12.13 6.63 -37.00 12.10 1331 April -5.25 5.16 -31.10 14.50 1181 May 1.27 3.63 -17.50 25.60 1250 June 6.07 3.80 -6.70 33.30 1258 July 10.23 3.91 -2.80 33.30 1286 August 10.47 3.52 -2.80 32.70 1234 September 6.91 3.38 -6.70 29.00 1283 October 1.21 3.33 -19.00 19.40 1226 November -5.24 4.61 -24.40 11.70 1244 December -12.80 6.87 -41.50 6.70 1295

Table 3-29 Monthly Air Temperatures for Makkovik (1983 to 2003) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -20.17 5.80 -39.50 0.00 62 February -17.09 6.50 -34.50 5.00 64 March -12.40 5.94 -30.00 7.50 87 April -4.43 8.47 -28.50 16.00 56 May 2.67 3.66 -9.50 20.50 62 June 7.93 4.80 -5.00 29.50 60 July 12.59 4.64 0.00 34.50 62 August 12.37 3.90 -2.50 29.00 62 September 6.73 3.10 -3.50 21.00 30 October 2.49 2.59 -11.50 15.50 31 November -3.33 4.65 -25.00 10.50 47 December -13.43 5.84 -27.50 3.00 51

Table 3-30 Monthly Air Temperatures for Hopedale (1942 to 1984) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -16.50 7.59 -40.00 5.60 1322 February -15.52 7.65 -40.00 7.20 1189 March -11.14 6.65 -35.00 10.00 1302 April -5.05 5.10 -28.20 11.80 1256 May 1.37 3.14 -17.20 28.30 1302 June 6.22 4.11 -5.60 31.10 1230 July 10.64 4.17 -1.10 33.30 1302 August 10.82 3.34 1.10 29.40 1257 September 7.45 3.41 -5.00 25.60 1200 October 2.09 3.28 -12.20 20.60 1271 November -3.49 4.20 -20.60 12.90 1258 December -11.37 6.70 -30.00 8.90 1302

Table 3-31 Monthly Air Temperatures for Cape Harrison (1943 to 1961) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -14.11 7.89 -35.60 7.20 558 February -13.41 7.88 -35.00 9.40 521 March -9.55 6.60 -31.70 11.10 544 April -3.82 5.29 -29.40 15.60 510 May 2.09 4.19 -14.40 31.70 558 June 7.36 4.81 -5.00 33.30 540 July 12.20 4.66 0.00 36.70 557 August 12.18 3.84 0.00 30.00 558 September 8.45 4.03 -3.30 29.40 509 October 3.14 3.74 -9.40 21.10 558 November -2.45 4.09 -19.40 16.10 570 December -8.93 6.41 -30.00 12.20 585

Table 3-32 Monthly Air Temperatures for Cartwright (1934 to 2003) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -13.93 7.36 -37.80 11.80 2108 February -12.92 7.41 -34.50 11.70 1972 March -8.53 6.56 -32.20 16.40 2107 April -2.47 4.66 -25.60 18.20 2040 May 2.95 3.76 -15.00 30.00 2108 June 8.37 4.57 -5.60 35.30 2039 July 12.50 4.14 -1.70 36.10 2104 August 12.27 3.58 -0.60 33.00 2134 September 8.66 3.51 -5.00 30.00 2070 October 3.24 3.29 -11.70 23.30 2076 November -2.16 4.30 -21.10 17.60 2070 December -9.10 6.44 -33.90 13.30 2108

Table 3-33 Monthly Air Temperatures for Mary’s Harbour (1983 to 1998) Average Daily Temperature Extreme Daily Temperature # Obs Mean (°C) St.Dev. (°C) Min (°C) Max (°C) January -14.22 6.82 -33.00 5.20 427 February -13.24 7.04 -33.80 5.00 378 March -8.32 6.25 -33.20 9.40 430 April -1.82 4.10 -24.50 14.70 424 May 3.35 3.57 -11.40 26.50 425 June 8.36 4.50 -3.30 35.60 392 July 12.54 4.16 0.00 31.00 425 August 13.16 3.79 0.20 32.60 423 September 9.04 3.18 -4.00 27.60 411 October 3.37 3.22 -11.40 19.00 434 November -2.68 4.64 -21.20 13.70 419 December -9.40 6.66 -31.20 9.20 432

3.5.2 Wind Chill Wind-chill is an important safety consideration for offshore personnel. It is commonly defined as a rate of cooling on an exposed surface due to the combined effects of wind speed and temperature, and is usually measured in Watts/m2 (W/m2). It is used to quantify the rate of heat loss from exposed flesh and measures discomfort and/or danger from prolonged exposure to adverse weather conditions. Some basic guidelines are presented in Table 3.34 and monthly wind-chill statistic plots from the Marine Climatology Atlas-Canadian East Coast are provided in Figure 3.31.

Figure 3.30 Mean, Minimum and Maximum Monthly Temperature for Weather Stations within Labrador Shelf SEA Area

Table 3-34 Basic Wind-chill Guidelines Wind-chill Description (W/m2) 700 Comfortable when dressed for skiing 1,200 No longer pleasant for outdoor activities on overcast days 1,400 No longer pleasant for outdoor activities even on sunny days 1,600 Freezing of exposed skin begins for most people 2,300 Outdoor travel becomes dangerous. Exposed flesh may freeze in less than 1 minute

Figure 3.31 Wind-chill Plots

Source: after AES 1985.

3.5.3 Shipping Visibility is often used as a criterion to assess shipping conditions, and incorporates variables such as fog, precipitation and freezing spray. The ranges for shipping visibility categories are defined as:

• visibility <0.5 nautical miles (nm); • 0.5 nm to 1.1 nm • 1.1 nm to 2.2 nm; • 2.2 nm to 5.4 nm; and • visibility ≥ 5.4 nm. Visibility statistics for the south Labrador coast, offshore OWS Bravo, northwest Labrador Sea, are illustrated in Figure 3.32. The Northern Grand Banks is included for comparison purposes. In general, shipping visibility is better on the south Labrador coast, except for January and December. During the summer months, shipping visibility on the northern Grand Banks decreases considerably, whereas it remains relatively constant off the south Labrador coast.

Source: after AES 1985.

3.5.4 Flying In addition to ship support, offshore facilities depend on helicopter service for operations support and/or search and rescue. Ceiling and visibility criteria must be met before helicopters can take off or land. The ceiling and visibility ranges reported by ships are defined as:

• visual flight rules (VFR): visibility ≥2.2 nmi and ceiling ≥ 1,000 ft; • instrument flight rules (IFR): 0.5 nmi ≤ visibility <2.2 nmi and ceiling ≥300 ft or ceiling <1,000 ft; and • below IFR: visibility <0.5 nmi or ceiling <300 ft. These are not actual visual meteorological condition (VMC) or instrument meteorological condition (IMC) limits but are based on the coding format used by ships-of-opportunity; however, they correspond reasonably well with the actual limits. The approximate flying visibility statistics for the south Labrador coast, OWS Bravo and the northwest Labrador Sea are illustrated in Figure 3.33. The northern Grand Banks is included for comparison purposes. In general, Labrador has better flying conditions from a visibility standpoint than the northern Grand Banks.

Source: after AES 1985.

3.6 Ice Conditions

3.6.1 Sea Ice Occurrence and Concentration Historical pack ice information covering the SEA region was compiled using the ICE ’06 (Canatec 2007) pack ice database software which contains various sources of data (i.e., Canadian Ice Service (CIS), National Ice Center (NIC) and Arctic and Antarctic Research Institute (AARI). Two CIS regional datasets (Eastern Coast and Hudson Bay) are required to cover the entire SEA Area. This creates issues regarding tying in data from both datasets, because entries are not necessarily representative of the same date. Therefore, NIC dataset was selected for pack ice analysis. The SEA Area dataset covers 35 years from 1972 to 2006, inclusive. Data was selected on a 0.5 degrees latitude × 0.5 degrees longitude grid spacing for the entire SEA Area. In earlier years, these data were collected through airborne reconnaissance. Satellite images supplemented airborne observations in the 1970s and replaced them as the principal source of pack ice information in the 1990s. Data are reported on a weekly basis each year for the entire range of years. Occasionally, gaps in the data in the middle of the ice season indicate that a measurement was not made. These were treated as missing data in the analysis.

Sikumiut Environmental Management Ltd. © 2008 August 2008 136 LABRADOR SHELF OFFSHORE AREA SEA – FINAL REPORT The mean annual number of weeks of pack ice found in the SEA Area is shown in Figure 3.34. Mean monthly concentrations when ice is present in the region are shown in Figures 3.35 to 3.46. It should be noted that for clarity, only the 200, 1,000 and 3,000 m bathymetry lines are shown in these figures. In general:

• the average start of the ice season ranges from mid-November in the north, to December, in the south. Ice growth typically continues until late spring, when the pack ice begins to melt and dissipate through the month of July. The ice season ends, on average, by late-June/early-July in the south but extends until late-July/early-August in coastal and northern regions • the mean annual number of weeks for ice presence is one week in the offshore areas to 28 weeks near shore in the north to one week in the offshore area to 20 weeks near shore south of Groswater Bay (Figure 3.34); • the average annual concentration in the vicinity of the banks is 3/10 to 4/10, decreasing with distance from shore. This observation includes all conditions (including areas designated as open water and ice-free); • when ice is present, the mean annual concentration varies from 3/10 to 9/10 over the entire SEA Area; and • multi-year ice concentration displays a high degree of variability. Occasionally occurring in small areas of concentrations of 2/10, it tends to appear in trace amounts within the overall pack throughout most of the season. This is discussed in further detail in Section 3.6.5.

Figure 3.35 Mean Monthly Pack Ice Concentration When Present for January