Soaring with eagles

090414-SierraStories

Meteorologists call it The Monster, a powerful mountain lee wave that forms to the east of the Sierra Nevada in the Owens Valley of California.

The Owens Valley is a visually stunning region that contrasts the towering, granite ridgeline of the High Sierra with a desert valley that is protected from the severe storms that frequently rage in the upper elevations. Not only is there the rugged Sierra to the west, but the majestic White-Inyo Mountains stand tall to the east. Both mountain ranges boast peaks that tower 10,000 feet above the valley floor and are separated by only 20 miles. Owens Valley is a remarkable place, a dramatic zone where climate and geology combine to enthrall geographers and photographers.

Mountain lee waves form downwind of mountain ranges around the world, including Lake Tahoe, but the powerful lift exhibited by the Sierra Wave is unusual in its force. The lee wave itself is invisible, but a sure sign of its presence are lenticular clouds, also known as wave clouds, commonly observed when the jet stream is in close proximity during the winter and spring months.

Much like the ripples in a stream, lenticular clouds form about 5 or 10 miles downwind from where air flows up and down over mountain peaks and troughs. They are an unusual, distinct cloud, with a smooth, layered appearance, a flat bottom, and the curved upper surface of an airplane wing. Similar to a flowing stream’s ripple, lenticular clouds appear stationary, but air passes through them at speeds from 50 to 100 mph.

The same topographic features that make Owens Valley such a photogenic tableau also generate powerful forces in the atmosphere that create an extraordinary lee wave, a phenomenon that has attracted sailplane pilots from California and around the world. Due to the extreme terrain variations in the Eastern Sierra near Bishop, the region has become a focal point for scientists attempting to better understand the atmospheric dynamics of wave clouds and its formidable sister, the dangerous, turbulent rotors that form at the surface.

The upward motion of the wave cloud can extend into the stratosphere, more than 60,000 feet in altitude, with uplifts and downdrafts that can rise and fall at incredible speeds between 2,000 and 4,000 feet per minute.

In 1947, two pilots from Bishop began a flying service in the area and soon were spending much of their time exploring the dynamics of the Bishop Wave, as it was initially called. In 1950, one of the pilots, Bob Symons, flew his P-38 powered aircraft into the Bishop Wave, cut the engines, feathered the propellers and soared for more than an hour on the powerful lift. Afterwards, several entities joined forces to sponsor the Sierra Wave Project, the first international meteorological study of these amazing mountain winds.

Among the representatives was Harold “Hal” Klieforth, a 23-year-old mountain meteorology graduate student. Klieforth had been drafted into the military during the summer of 1945 and at one point he had the opportunity to watch an Air Force meteorology officer create detailed weather maps before a scheduled flight. Fascinated with weather and aviation, he entered UCLA to study meteorology.

After he heard the airport manager at Bishop in the Owens Valley talk about a world record flight to an altitude of 36,100 feet that he had recently made with another pilot, Klieforth became UCLA’s Project Scientist and field representative based full-time in Bishop. The university’s essential goal was to define airflow in the lee of the mountains during the mountain wave phenomenon. One of the key tools they used to develop an understanding of the mountain wave was instrumented sailplanes, which were considered significantly better than powered aircraft for the study. Fuel was an obvious limitation for internal combustion engines, but sailplanes by definition use the atmosphere for lift. Over the next few years, scientists steadily improved their two-seat sailplanes as they sent teams higher and higher into the atmosphere. The planes had a self-contained oxygen system, but cockpits were not pressurized.

Technology made ascents into the stratosphere possible, but severe cold during the long-duration, high-altitude flights caused problems. Outside temperatures exceeded 100 degrees below zero, with a minus 50 degrees once measured on the interior instrument panel. The brutal temperatures inflicted varying degrees of frostbite on the feet of every pilot and crew, and at one point every flight member was limping.

As the project progressed, flights started to regularly exceed 40,000 feet, until finally, on March 19, 1952, a sailplane manned by team members Klieforth and Larry Edgar set a world record for the highest flight in a two-man glider (44,255 feet in an unpressurized cockpit). It was an aviation benchmark that stood for years. More than a half century later, in 2009, two men flew a glider above the Andes Mountains to set the current World Altitude Record of 50,699 feet.

At 87 years of age, Klieforth is still going strong doing scientific research in the Owens Valley, where he climbs mountains, installs remote weather stations, and tends to his weather and climate research library in Bishop.

On May 31, 2011, Gordon Boettger, a FedEx pilot from Minden, Nev., established the longest flight in the Northern Hemisphere in a sailplane when he flew his single seat glider 1,401 miles, parallel along the Sierra in 13 hours, 17 minutes. Taking advantage of high winds and long hours of daylight, Boettger’s motorless aircraft was towed into the air from the Minden-Tahoe Airport on a day that Doug Armstrong, a retired meteorologist who is part of Boettger’s team, had predicted was perfect for this record aviation attempt.

Once airborne, Boettger steered his plane south and headed for the lower Owens Valley. Taking advantage of the powerful Sierra Wave lift that peaked at more than 1,000 feet per minute at times, he soared to a maximum altitude of 28,400 feet. To avoid possible interference with commercial aircraft, Boettger’s sailplane was tracked by the Federal Aviation Administration’s Air Traffic Control in Oakland and southern California. The aircraft reached ground speeds of 165 mph on the northbound return due to a vigorous southwest tailwind. Boettger made the final leg of his trip in just 96 minutes, averaging 158 mph.

To experience your own epic soaring adventure, head over to Soar Truckee, Inc. in the Martis Valley where expert pilots will help you fly with the eagles.

Tahoe historian Mark McLaughlin is a nationally published author and professional speaker. His award-winning books are available at stores or at thestormking.com. Mark may be reached at mark@thestormking.com. Check out Mark’s blog at tahoenuggets.com.

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Mark McLaughlin
Tahoe historian Mark McLaughlin is an award-winning, nationally published author and professional speaker with seven books and more than 800 articles in print. A prolific writer, Mark has received the Nevada State Press award five times. He is a popular lecturer and experienced field trip leader who has lived at North Lake Tahoe since 1978. He teaches Sierra Nevada history using entertaining stories, slide shows and informative tours. He has been a frequent guest on National Public Radio and has appeared as an expert consultant on CNN, The History Channel and The Weather Channel, as well as many historical documentaries.