The Titanic disaster spurred many maritime nations to examine the safety of their vessels on the open ocean. Since the Safety of Life at Sea treaty (SOLAS), which went into effect July 1, 1915, the U.S. government (through the Coast Guard and before that the Revenue Cutter Service) performs the operational duties of the International Ice Patrol with funding from international signatories. Since then, patrols have been conducted each year, with the exception of a brief period during World War II.
The region known as the Grand Banks of Newfoundland is of particular interest for several reasons. First, the great circle route connecting the U.S and Canada with Europe crosses right through this area. This means that there is a high volume of merchant vessels that need to cross this treacherous region. Second, the Grand Banks is home to very productive fishing grounds, which makes it especially attractive to commercial fisherman; this only serves to compound the high traffic density. Finally, the adverse environmental conditions (high winds, rough seas, and dense fog) make this locale even more dangerous.
Probably the most important environmental factor to consider is the dense fog that often occurs on and near the Grand Banks. This occurs when the southern flow of the Labrador Current joins the warm Gulf Stream waters at the tail of the Banks. As warm Gulf Stream winds flow over the cold Labrador Current, an advective fog forms that can last for many days. This dense blanket of fog severely limits visibility and restricts a vessel?s ability to maneuver. Furthermore, the upper-level jet stream frequently flows right over this region. As a result, low-pressure mid-latitude systems often move through, bringing severe weather with high winds and large seas.
The oceanographic structures in this region also contribute to the danger around the Grand Banks of Newfoundland. The principal contributors to this are the Labrador Current and the bathymetry. The Labrador Current is the main ocean current responsible for transporting icebergs into this region. It is a relatively fast-moving current that stays cold enough to carry icebergs all the way from the Labrador Sea and Baffin Bay to southern temperate waters. In fact, Titanic sank at the latitude of Providence, R.I. The bathymetry is also responsible for the transport of icebergs, but it has more impact on where the icebergs flow rather than how fast.
Due to the fact that the majority of an iceberg?s mass lies below the water, their track is greatly governed by sub-surface currents. The depths of these currents, like the Labrador, often dictate that they follow the 1,000-meter curve. The result of this is that icebergs commonly track through the gap between the Grand Banks and the Flemish Cap, affectionately termed "iceberg alley."
Due to the constant dangers in this area, the International Ice Patrol (IIP), operating out of Groton, Conn., maintains an ever-vigilant watch over the North Atlantic and reports the Limit of All Known Ice (LAKI) for the Grand Banks of Newfoundland and the surrounding area. Seasonal patrol dates have remained largely unchanged from year to year. Reconnaissance usually begins in late February and continues through July, but the exact dates vary from year to year as dictated by the distribution of icebergs. The longest season on record was in 1992, which lasted from February 7 to September 26, for a total of 203 days. Conversely, in 1999 the season never opened due to the fact that most icebergs were pushed west rather than south. Except during extreme years, the Grand Banks are generally clear of ice from August to February with the exception of a few stray icebergs.
Today the International Ice Patrol uses HC-130H Hercules aircraft, which can cover more than 2,000 nautical miles and fly for more than 12 hours. They use planes out of Elizabeth City, N.C., that are equipped with forward- and side-looking airborne radar for iceberg detection. Each flight covers an average of 30,000 square miles of ocean searching. Visual observations are conducted when conditions allow, but due to low cloud ceilings and the dense fog described earlier, good visibility exists about 30 percent of the time. During the main ice season, IIP’s reconnaissance detachments deploy their aircraft to St. John?s, Newfoundland.