Like katabatic winds, it is driven by the flow of an elevated, high-density (usually cold) air mass into a lower-density (warmer) air mass, but the term fall wind is restricted to the cases where the cold air mass is not due to radiative cooling of a slope, but to the presence of a dense air mass at the top of a slope.
[1] A well-known example of a fall wind is the Bora in the Adriatic sea region, to the extent that the term ‘bora wind’ is sometimes used to designate a fall wind.
[2] The presence of the dense (cold) air mass at the top can be caused by various meteorological phenomena, such as the arrival of a cold front,[1] or from the advection of cool marine air by a sea breeze.
[3] The flow of the dense air mass during fall winds events is similar to the flow of water over a dam, with a hydraulic jump found downstream.
[4][3] Examples of fall winds are the Bora in the Adriatic, the Athos fall wind[5] in Greece, or the Marinada in Catalonia.