Perturbations that bring storms are formed when there is a collision between two air masses at different temperatures or when the excessive heating of the ground, along with a high level of humidity, brings about the formation of masses of warm, humid air. The mechanism is the same as that which leads to the formation of fronts and cloud systems (ascent, cooling and condensation), but owing to the great differences in temperature, the phenomenon is more intense and ‘energetic’. Storms are therefore typical of warm, humid regions, such as tropical and subtropical zones, or our latitudes during the summer months. The mechanisms that lead to the formation and evolution of storms were studied at the end of the Forties at the University of Chicago in a research programme called Thunderstorm Project, that brought to the construction of a clear picture regarding these atmospheric phenomena.
The indicators connected to a storm cloud (winds, precipitation even including hail, lightning) can be very violent and destructive and in particular conditions storms can evolve into tornadoes or whirlwinds.

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