Climbing out near Bishop, California in the Soar the Sierra ASK 21.

 

 

 

Soaring in the White Mountains, the Inyo Mountains, and the southern Sierra calls for special techniques because of the tremendous terrain relief between the floor of the Owens Valley and the tops of the ridges.

Tutorial: Climbing On Top of the Whites

 

The White and Inyo Mountains are famous in the literature of soaring, and rightfully so. Where else in the world is it frequently possible to cover well over one hundred kilometers at Vne, and just below 18,000 feet, without stopping or turning? Paradoxically, it is sometimes difficult for visiting pilots to climb to the top of the Whites from their release altitudes, and over the years many pilots have wondered about the technique involved. The following is a brief summary of these techniques.

Unlike operations at most other soaring sites, it is impractical to release near the ridgetops; the White Mountains are nearly 10,000 vertical feet above the airport at Bishop, and in fact recent laser studies suggest that White Mountain Peak is actually higher than Mt. Whitney. (Mt. Whitney has long been listed as the highest peak within the contiguous 48 states.)

Releasing at 2,000 feet above the airport elevation means that there are still nearly 8,000 feet to gain before actually cresting the White Mountains, and this is almost unique in US soaring. A further complication is that the Owens Valley, between the White and Inyo Mountains and the Sierra, is not only deep, but quite narrow. This means that early in the day, when a long cross-country flight is likely to begin, what light winds are present are virtually always parallel to the axis of the valley rather than blowing onto the slopes. This, in turn, means that the light upslope breezes that would typically trigger thermals are absent, as is the ridge lift itself.

The solution to this dilemma is to search for situations in which anabatic flow is likely to be present. Anabatic flow occurs when the thin layer of air adjacent to the terrain is heated by conduction and flows upslope while still being heated by the surface over which it is passing. This layer of rising air is too thin to be used directly by sailplanes--at least as long as it remains attached to the surface.

The lower slopes of the White Mountains feature numerous small peaks that are shallow enough on all sides to prevent the formation of shadows at 11:00 am to noon, the time of day when a flight commonly begins, and so many of them will have anabatic flow on all sides. When the air, slowly flowing up the side of one of these little peaks, reaches the peak, it can’t descend down the other side—because it meets the air from the other side which is also rising. The only real possibility is for the airstreams to merge into a tiny thermal.

The technique for exploiting this anabatic flow in a sailplane is to make passes exactly as if ridge soaring, seeking out the little peaks likely to sprout these tiny thermals. These thermals will generally be too small to safely circle in, and so the best technique is simply to try to “connect the dots” to the extent possible--combined perhaps with a little judicious dolphin flying.

In this way you will slowly gain altitude, which in turn will allow the temperature advantage of higher terrain to work for you: as you climb the thermals will become larger, stronger and better organized. Sometime before it will be safe to circle in these thermals, you will find it advantageous to fly very short ridge passes—in essence, to fly Figure 8s—so as to make best use of each thermal without prematurely committing yourself to completing a low turn into rising terrain. Ultimately it will become possible to circle in thermals, as usual—at which point it will no longer be necessary to use any special techniques.

Early in the day, you may find it necessary to repeat this cycle once or twice on your way to the top of the Whites; reaching the top of a thermal at, say, 13,000 feet, simply angle in toward the most promising nearby terrain within easy reach and begin making ridge passes once again.

In summary, you will begin your climb using standard ridge-soaring passes (dolphining where appropriate and safe), transition to Figure 8s, then finally to spiraling in thermals.  Repeat as necessary.

Using these techniques, you should find that the initial climb to the top of the White Mountains takes only twenty minutes or so.  This is quick enough that if your planned flight takes you out toward Tonopah, it is easy to arrive there before good thermals will have had time to form.  Consider placing your first turnpoint toward the south end of the Inyo Mountains--abeam Lone Pine, perhaps, or over Cerro Gordo.  This will allow you to cover a fair distance while waiting for the Tonopah area to heat up for your arrival there.

 

A reminder: as you climb, your density altitude—and therefore your turn radius—will dramatically increase! Always allow yourself plenty of margin, and bear in mind that in the clear air above 10,000 feet it is extremely difficult to “eyeball” distances.