Clouds are often very important indicators of imminent weather changes.
When they are observed at various times and regular intervals, even an approaching mid-latitude storm can be recognized. In an approaching storm, a change of cloud structure and type will take place. First, high cirrus clouds appear, followed by high-level cirrostratus clouds and low thick altostratus clouds. When the storm is finally close at hand, dark clouds will bring high winds and pouring rainfalls. But how do clouds form? Clouds are nothing more than water vapor that condenses on microscopic airborne particles, like dust and sea salt, which then accrete into a visible form.