full text of the classic FAA guide
Records are made to be broken. Altitude and distance records are a prime target of many sailplane enthusiasts. Distance records may be possible by flying a combination of lift sources such as thermal, frontal, ridge, or wave. Altitude records are set in mountain waves. Altitudes above 46,000 feet have been attained over the Rocky Mountains; soaring flights to more than 24,000 feet have been made in Appalachian waves; and flights to as high as 20,000 feet have been recorded from New England to North Carolina.
We sincerely hope that this chapter has given you an insight into the minute variations in weather that profoundly affect a soaring aircraft. When you have remained airborne for hours without power, you have met a unique challenge and experienced a singular thrill of flying.