Gravity winds are winds that flow downhill under the pull of gravity. They occur mostly in mountainous or glacial regions where cold dense air from the mountain or glacier tops flows down the slopes under the influence of gravity. When the slopes are particularly steep, the cold air can gather tremendous kinetic energy giving very strong winds.
The strongest gravity winds ever recorded are the katabatic winds in Antarctica, where extremely cold air travels from the continental interior, which is an ice plateau averaging more than 2km in height, to the coast. Gale force winds are frequently recorded near the coastal region. The strongest on record is 327 km per hour in 1972.