As a stiff wind is disturbed passing over a mountain ridge, the resulting Mountain Wave can cause ripples in the air reaching altitudes up to 35,000 feet. Catching a rising column of air and riding that wave up to the edge of the stratosphere requires supplemental oxygen and a set of large stones.
Cowley Airfield in Alberta, Canada is renowned for its unique location on the foothills of the Rocky Mountain Livingstone Range where the cold, dry, Chinook winds are flung off a swirling low pressure in the Gulf of Alaska, swoop south towards Montana, and crosses perpendicular to the Rockies at speeds upwards of 90 mph.
As the wind crests the top of the peaks the air is forced down the leeward side of the mountain and a series of oscillating up and down drafts are formed. Lenticular clouds are the most unmistakable presence of a mountain wave as the round disc-like cloud forms at the crest of a standing wave.
A lenticular cloud produced by a mountain wave. (Wikipedia Commons)
Twice a year a soaring camp is held at the Cowley airfield including a week long event in October as the winter winds begin to make their way south, but before the Canadian landscape turns to a frozen tundra. This week offers the best chance at record breaking altitude attempts and competitions including time aloft, distance and altitude are conducted.
Sailplanes are generally towed with a powered aircraft to an altitude of 2,000 feet where they are released and left to the whim of the atmosphere and the wit of the pilot to find rising air and maintain altitude, or turn back and glide to a landing. Once a pilot catches a rising mountain wave, a eery smoothness settles over the airplane as the elevator ride begins to lift the craft to heights reserved for airliners.
Normally flights above 18,000 feet are not allowed for operations under visual rules and require a flight plan and an appropriately equipped aircraft to fly any higher. Arrangements have been made this week with air traffic control to open up a "Wave Window" for all aircraft to legally fly within that block of airspace.
Oxygen is required above 14,000 feet and flight above 25,000 feet is not recommended. With temperatures colder than 40º below zero and very little oxygen, the time of useful consensus at 25,000 feet is 180 seconds and your time is halved by simply climbing to 27,000 feet. This give the pilot very little opportunity to make corrective action in the event of an emergency and guidelines for handling hypoxia are taken very seriously.
The current altitude record by an unpowered aircraft is held by Steve Fossett who flew to an height of 50,720 ft in 2006. Steve broke many other records before he mysteriously disappeared during a flight in the Sierra Nevada mountains. A widely publicized manhunt was abandoned and the crash site wasn't found till a year later a hiker happened upon the accident.