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Katabatic wind

A gravity-driven wind formed when cold, dense air drains downhill off a high plateau or glacier — often offshore, often ferocious.

Also known as: drainage wind, fall wind

Cold air is dense. Let it sit on a plateau, a glacier, or a snow-covered mountain range, and gravity eventually pulls it down to sea level. That collapsing air mass is a katabatic wind — gravity-driven, usually cold and dry, sometimes very strong.

Classic examples:

  • Bora — Adriatic coast, 30–60 kt in winter, gusting well past 80
  • Mistral — Rhône valley, partly synoptic but with strong katabatic reinforcement
  • Antarctic coast — the most consistent katabatic flow on Earth
  • Fjord exits in Norway, Greenland, Patagonia

For riders, katabatic winds matter because they tend to be:

  • Offshore (cold air drains seaward from continental interiors)
  • Very gusty — gust factors of 1.5+ are normal
  • Underforecast by global models that smooth the terrain that funnels them

If a forecast at the foot of a major mountain range shows light wind but the inland air mass is freezing, treat any offshore reading with healthy suspicion. See Types of Wind for the wider taxonomy.

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