Valley Inversion (Cold Pooling)
Overview
A valley inversion, also known as cold pooling, occurs when cold, dense air settles into low-lying valleys, creating temperature differences between valley floors and surrounding slopes.
Key points
- Common during calm, clear nights in mountainous terrain.
- Results in significantly colder temperatures at lower elevations.
- Influences campsite selection and overnight comfort.
- Can contribute to frost, dew, and condensation buildup.
Details
During a valley inversion, radiational cooling allows cold air to accumulate in depressions while warmer air remains higher on slopes. Hikers camping in valley bottoms may experience unexpectedly cold conditions even when forecast temperatures are moderate. Choosing higher, well-ventilated campsites can reduce exposure to cold pooling effects. Inversions also affect air quality and fog formation.
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Illustrative hiking footage
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