Minicyclones

A minicyclone is a small-scale weather phenomenon characterized by a localized area of rotating winds. These events are much smaller than typical cyclones, often measuring only a few meters to a few kilometers in diameter. They are not associated with large-scale weather systems like hurricanes or extratropical cyclones.

Minicyclones can form under various atmospheric conditions, often in the presence of strong winds interacting with surface features such as buildings, hills, or even vegetation. They can also occur in the absence of significant surface obstacles, sometimes referred to as "thermal minicyclones" when driven by localized heating. The rotation is typically counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere, similar to larger cyclones, due to the Coriolis effect, though this effect is often minimal at such small scales.

While generally weak, minicyclones can be strong enough to cause localized damage, such as scattering debris or uprooting small plants. They are often observed as dust devils or whirlwinds, where rising air from heated ground carries dust and debris into the rotating column. However, not all minicyclones are visible; they can occur in areas with no loose surface material. Their transient nature and small size make them difficult to predict and study systematically. Meteorologists often observe them as interesting, localized atmospheric disturbances rather than significant weather threats.