The Grand Banks is a large area of continental shelf, extending up to 310 miles (500 km) off Newfoundland. The area is renowned for dense sea fogs, which arise when warm, moist air from the south is chilled by the cold Labrador Current, causing condensation. The Labrador Current presents another shipping hazard by bringing icebergs to the area—the Titanic famously sank south of the Grand Banks in 1912.
Although turbidity currents have never been directly observed, their power was felt in 1929 when an earthquake triggered a huge sediment flow (submarine landslide) down the continental slope off the Grand Banks. Submarine telegraph and telephone cables were broken over a distance of 500 miles (800 km)—from the timing of the breaks, the speed of the flow was estimated at 25–34 mph (40–55 km/h).