Explanation: A katabatic wind (named from the Greek word katabasis, meaning "descending") is the technical name for a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds; the spelling catabatic winds also occurs. Katabatic winds can rush down elevated slopes at hurricane speeds, but most are not as intense as that, and many are of the order of 10 knots (18 km/h) or less.