Final answer:
An altitude dive is a dive made at an elevation higher than 2,000 ft. (600 m) above sea level, and special considerations are needed due to the decreased atmospheric pressure at higher altitudes.
Step-by-step explanation:
With most dive tables and computers, an altitude dive is a dive made at an elevation higher than *2,000 ft. (600 m)* above sea level.
Altitude diving requires special considerations due to the decrease in atmospheric pressure with increasing altitude. This can affect the dive planning, decompression requirements, and equipment considerations. The altitude dive tables provided for these purposes take into account the reduced pressure and adjust the dive profile accordingly.
For example, at an altitude of 10,000 ft. (3,000 m) above sea level, the ambient pressure is lower than at sea level, which requires adjustments to the no-decompression limits and decompression stops. These adjustments are necessary to prevent decompression sickness and other related risks.