Clouds are formed when invisible water vapors condenses into air and droplets or ice crystals are formed. Water enters into the air through evaporation process. The are few necessary steps for storm formation. The sun heats the surface of the earth and warm air rises into the upper most atmosphere where temperature is lowered. Water vapors condenses from the surface and rises to the upper atmosphere water droplets freeze in upper atmosphere because of reduce temperature and then ice or water droplets fall.