During the threat of an oil spill, responders need to know where that spilled oil will go in order to protect shorelines with containment boom, stage cleanup equipment, or close areas for fishing and boating. In order to answer these questions, NOAA oceanographers use specialized computer models to predict the movement of spilled oil on the water surface. They predict where the oil is most likely to go and how soon it may arrive there. During a major spill response, trajectory maps are created to show predictions for the path of spilled oil.