Containers occasionally fall from ships, usually during storms; according to media sources, between 2,000 and 10,000 containers are lost at sea each year. The World Shipping Council states in a survey among freight companies that this claim is grossly excessive and calculated an average of 350 containers to be lost at sea each year, or 675 if including catastrophic events. For instance, on November 30, 2006, a container washed ashore on the Outer Banks of North Carolina, along with thousands of bags of its cargo of Doritos Chips. Containers lost in rough waters are smashed by cargo and waves, and often sink quickly. Although not all containers sink, they seldom float very high out of the water, making them a shipping hazard that is difficult to detect. Freight from lost containers has provided oceanographers with unexpected opportunities to track global ocean currents, notably a cargo of Friendly Floatees.