Colder water off Seward, Alaska, imaged by the NOAA-11 polar orbiting satellite coincides with the leading part of the oil spilled from the Exxon Valdez. Visual observations from a National Oceanic and Atmospheric Administration airplane suggest that the location of the cooler radiant temperature on the image (Figure 1) was the leading edge of the spill, which was about 180 km southwest of Bligh Reef in Prince William Sound, where the tanker ran aground March 24.

The spill was carried to its April 7 position by wind and the Alaska Coastal Current at an average speed of 15 cm s⁻¹ (about 13 km a day). Wind and fresh water discharge drive the coastal current, which is unusually slow due to record low precipitation in southeastern Alaska in February.