In the United States, an intermittent stream is one that only flows for part of the year and is marked on topographic maps with a line of blue dashes and dots. In desert areas of the American Southwest, this also includes washes, which only flow after thunderstorms or other significant rains. A blue-line stream is one which flows for most or all of the year and is marked on topographic maps with a solid blue line. In Australia, an intermittent stream is usually called a creek, and marked on topographic maps with a solid blue line.