If a great number of radio waves are reflected back from a particular area, it indicates that the atmosphere in that area has a high concentration of water droplets or ice particles. This phenomenon is known as radar reflection or radar echo, and it is often used in weather forecasting to detect precipitation, such as rain, snow, or hail. The amount of radio waves reflected back from the area can give scientists an idea of the intensity and location of the precipitation, which can be used to create weather maps and forecast the weather in that area.