Flying the Invisible Currents: Reflections on Mountain Flying Across the Western United States

In the mid-1990s, I conducted several long cross country trips across the United States where I encountered some of the most vivid lessons in mountain flying. Each leg of the journey taught me something unique about the interaction between terrain, weather, and pilot judgment, and not always in ways that could be anticipated from textbooks.

One flight that remains particularly vivid took me from Sandpoint, Idaho, to Boise in a Piper Archer. We were flying over mountainous terrain, far from the obvious ridges, yet encountered severe downdrafts. The winds were strong, and the air seemed to drop beneath us with a sudden intensity that felt entirely unnatural. I had flown extensively in the Rockies, the Sierra Nevada, the Alps, and the Saint Gabriel Mountains, even experiencing foehn winds in the northern Alps, yet I had never felt that kind of invisible force buffet the airplane. The experience was shocking and immediately humbling. It forced me to question whether the conventional mountain flying rules about upwind and downwind approaches were truly reliable, at least in situations where the air could ambush you far from the ridges.

Idaho, I learned, has a kind of continental mountain weather that can be deceptive. Unlike the Alps or the San Gabriel Mountains in Southern California, where the ocean or prevailing patterns often moderate the air, Idaho’s valleys and ridges can combine with strong winds and stable layers to create invisible subsidence lobes. You can be flying in smooth-looking air, only to encounter a downdraft that exceeds your climb capability - a scenario where textbook heuristics about upwind and downwind sides become unreliable. I realized that backcountry flying there is risky not because the strips are short or the terrain is dramatic, but because the air itself can turn hostile without warning. Narrow canyons amplify that risk, removing lateral and vertical escape options and leaving the pilot at the mercy of forces that are literally invisible.

I remember watching an episode of ABC’s The Wonderful World of Flying that covered Idaho backcountry operations. The presenter suggested that a pilot should have at least 200 hours of total time before attempting such flights. At the time, the show featured respected aviators like Barry Schiff, and its guidance carried weight in the aviation community. Looking back, I feel that the 200-hour benchmark was too optimistic. It underestimated the subtlety of mountain air and the invisible hazards that can arise even on seemingly normal days. Experience, mentorship, and a mature respect for the atmosphere are far more important than a simple hour count. The show’s advice was shorthand for caution, but the real Idaho experience demanded much more than that.

After that leg, we flew from Boise to Jackson, Wyoming, early in the morning. That flight was smooth, despite the valley setting. Jackson Hole is a broader valley than Sandpoint, and the early-morning timing meant that thermal activity had not yet developed and surface winds were light. The ride felt textbook, and the landing at Jackson was precise and uneventful. The contrast between this leg and the Idaho leg could not have been starker: the same pilot, same aircraft, but the difference in wind aloft, valley geometry, and timing created entirely different experiences.

Two days later, after visiting Yellowatone and Grand Teton National Parks, we continued from Jackson to Rapid City, South Dakota, crossing a high mountain pass and climbing to 12,000 feet. The flight was slightly bumpy but entirely manageable. The turbulence was obvious, thermally driven, and predictable - a far cry from the invisible downdrafts of Idaho. Flying at high altitude also reduced fuel burn, allowing us to skip a planned fuel stop in Casper, Wyoming. The decision to remain at altitude improved both efficiency and safety, providing greater glide margin and more time to respond to minor disturbances.

Reflecting on these flights, I see a common thread: the invisible geometry of air over mountains dictates the level of challenge, often more than the visible terrain itself. Idaho’s continental interior can ambush even experienced pilots with smooth-looking but dangerously sinking air. In contrast, broad valleys in the Rockies, like Jackson Hole, or the ocean-influenced San Gabriels, often produce forgiving conditions that reinforce confidence. Timing, wind direction, altitude, and aircraft performance all interact to create either hidden threats or manageable turbulence.

These experiences left a lasting impression on me. They taught me that rules of thumb in mountain flying are guides, not guarantees, and that situational awareness, humility, and respect for the air itself are as important as stick-and-rudder skill. The lessons from Idaho, Jackson, and the mountain passes between them remain etched in my mind, shaping how I think about the unseen forces that govern every mountain flight.