Snowmaking begins with a water supply such as a river or reservoir. Water is pushed up a pipeline on the mountain using very large electric pumps in a pump house. This water is distributed through an intricate series of valves and pipes to any trails that require snowmaking. Many resorts also add a nucleating agent to ensure that as much water as possible freezes and turns into snow. These products are organic or inorganic materials that facilitate the water molecules to form the proper shape to freeze into ice crystals. The products are non-toxic and biodegradable.