Precipitation creates runoff, which flows over the earth's surface to fill lakes and rivers. Water seeps into the ground through tiny fissures and replenishes the groundwater aquifer. These areas are usually located near oceans and other large bodies of water, which allows for more water to evaporate and form clouds. There is less precipitation further away from bodies of water and closer to mountains. As clouds travel over mountains, water vapour condenses to form precipitation or freezes. This is why there is usually snow on mountain peaks.