Winds and air currents that drain downhill when air in the upper slopes of a valley is cooled at night and so becomes denser. Katabatic flows in a valley are analogous to stormwater flows, both draining down gullies to the valley floor.

of an air current or wind; moving downward or down a slope because of cooling especially at night

describes a wind directed down a slope, caused by downhill drainage of cooler, dense mountain air. Katabatic winds in Antarctica tend to flow from the central ice dome down valleys and can be very strong.

wind blowing down an incline, such as down a hillside; downslope wind.