Alaska North Slope or Arctic North Slope, region, N Alaska, sloping from the Brooks Range N to the Arctic Ocean. In 1968 large petroleum reserves were found in the Prudhoe Bay area. In 1977 the 800-mi (1,287 km) Trans-Alaska pipeline was completed to carry oil S to the port of Valdez, on the Pacific. Proposals for oil and gas exploration in the Arctic National Wildlife Refuge, E of Prudhoe Bay, have brought continuing controversy. A 2003 National Research Council report on drilling concluded that lasting environmental damage had resulted because the harsh climate slows natural recovery and because there is little incentive to restore areas where drilling has ceased.