|
Like fog, clouds form when the air cools to its dew point. Clouds can form at any altitude in the troposphere. At temperatures
above freezing, clouds are made of water droplets. Below freezing, clouds are usually mixtures of snow crystals and supercooled
water, which is water that has cooled below 0°C without freezing. When supercooled droplets contact ice nuclei, they form
snow and ice crystals. at temperatures below -20°C , clouds are made up mostly of snow and ice crystals.
(McDougal Littell 'Earth Science')
|
