The visible length of the streak of lightning depends on the terrain and can vary greatly. In mountainous areas, where clouds are closer to the ground, the flash can be as short as 300 yards (273 meters), whereas in flat terrain, where clouds are higher above the ground, the bolt can measure as long as 4 miles (6.5 kilometers). The typical length is about one mile (1.6 kilometers), but streaks of lightning up to 20 miles (32 kilometers) have been recorded.