Surfers have Hawaii's North Shore, mountain climbers have Mt. Everest, and glider pilots have the Mountain Wave. You don't participate in these extreme sports without serious training, top notch equipment and the ability to manage risk. Flying a glider in a mountain wave is all that and more. For adventurous glider pilots, wave flying offers the possibility of extreme heights and record distances.
High altitude winds blowing across big mountains like the Sierras in California, the Rockies in Colorado, or the Andes in Patagonia, can form atmospheric standing waves resembling those formed in water flowing over a submerged boulder. See: http://en.wikipedia.org/wiki/Lee_waves
On January 21st, 2003, Klaus Ohlmann of Germany flew his Nimbus 4 DM glider 1870 miles in the lee waves of the Andes starting from Chapelco Apt. near San Martin de los Andes, Argentina to establish a world distance record.
What is a wave flight like? Let me describe one of mine. It was an unusually warm January morning in Colorado 30 years ago. A great "Lenticular" wave cloud floated stationary in the fast moving air at 25,000' MSL above the Continental Divide. An hour before takeoff, arrangements had been made by telephone with Denver Center for access into a "Wave Window" - an area above 18,000 feet, defined in a letter of agreement and available to glider pilots by request.
The takeoff was into a very turbulent, 20 knot west wind. I wore an insulated flight suit, boots, thick gloves and a sheepskin lined WWII leather helmet with a tight fitting oxygen mask as protection against the cold and lack of oxygen. I pulled the tow rope release knob at 11,000 feet and the tow pilot dove away with a radioed "Good Luck". The turbulence rolled and pitched the glider like a raft on the Colorado River making me work hard to maintain control - but I was climbing.
The turbulence suddenly ended as the glider entered the perfectly smooth air of the wave itself and the rate of climb increased dramatically. I could actually see the mountain peaks falling away. Denver Center granted a clearance into the wave window just before reaching FL180.
Now, facing into the jet stream climbing 2500 feet a minute, I concentrated on staying inside the assigned airspace while navigating around the upwind edge of the Lenticular cloud. In what seemed like the blink of an eye, the glider was above 30,000 feet and it was getting intensely cold. Ice was forming on the inside of the canopy as my breath froze. The outside air temperature was minus 40C and dropping but fierce sunlight provided a little warmth.
As the glider soared past 38,000 feet, I felt the "pressure demand" oxygen system automatically pushing pure oxygen into my lungs. At 42,000, the glider would go no higher. (I wasn't sure I wanted to go higher.) Jet contrails were visible BELOW my altitude. The slide rule glide calculator said I could glide more than 300 miles downwind to somewhere in Kansas. Instead, I just sat there for a few minutes taking in the view.
The cold seeping into my flight suit told me I needed to get down so I flew into the descending part of the wave which now carried the glider down even faster than it went up. As I rolled to a stop after a 40 minute flight, friends ran up with questions about how high the flight had gone. I tried to speak but my facial muscles refused to work - they were just too cold. I had surfed the jet stream at Flight Level 420 and no North Shore Kahuna could have been more satisfied.
Next time I'll write about sailplanes and their advanced technology. Meanwhile here's some great reading.
Exploring the Monster by Robert F. Whelan Amazon ISBN-10: 1891118323