Some of the most powerful effects will be seen on flatter coastal land abutting the shallows of large water bodies. If these areas also are prone to landfall by tropical cyclones, the effects will be further intensified. Among the hardest hit will be tropical and sub-tropical river deltas – broad fans of sediment and waterways where rivers meet the sea. Because such deltas often are the sites of port cities, large human populations will be exposed to significantly higher risk. Hot spots include the U.S. East Coast and Gulf Coast, Asia, and islands.