Katabatic wind
Topic: Atmospheric Pressure, Winds and General Circulation · NCERT: Class 11, Ch 9 "Atmospheric Circulation and Weather Systems"
Meaning
A katabatic wind is cold, heavy air that flows downhill under gravity. It starts over high plateaus and ice fields, where the air touching the cold surface becomes very cold and dense. This heavy air then drains down slopes and valleys, like water running downhill. Large ice sheets give the strongest katabatic winds, because they can supply cold air for long periods. The cold bora of the Adriatic Sea is one type.
Example
Fierce katabatic winds pour down from the Antarctic ice sheet to its coast, making it one of the windiest places on Earth. Similar winds flow off the Greenland ice sheet.
Don't confuse with
- Foehn wind: it also blows downhill, but it is warm and dry. It warms as air is squeezed on the way down after losing its moisture as rain on the windward side. Gravity pulling cold air down does not drive it.