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SESK: Stuff Everyone Should Know · sesk.info/ski-altitude-8000-ft

At about what sleeping altitude does altitude illness become a risk?

8,000 feet (2,450 m) or higher.

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  1. 8,000 feet (2,450 m) or higher ✔
  2. 3,000 feet (900 m)
  3. 15,000 feet (4,600 m)

Why: Unacclimatized travelers who sleep at 8,000 feet or higher are at risk. Many ski towns are that high, so take it easy on day one.

Huh, didn't know that: CDC notes the risk can also occur at lower elevations.

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How do mountains stay warm in winter? They put on their snowcaps.
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References

Answer: 8,000 feet (2,450 m) or higher. Unacclimatized travelers who sleep at 8,000 feet or higher are at risk. Many ski towns are that high, so take it easy on day one.

  1. CDC Yellow Book: High-altitude travel and altitude illness www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html
    Any unacclimatized traveler proceeding to a sleeping altitude of ≥2,450 m (≥8,000 ft)
    Checked 2026-10-10.

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