Thermal, Ridge, and Wave
Thermals with cloud bases of around 10,000' enable gliders with modest performance to cross the Columbia River canyon to the mountains west, to safely reach the spectacular destinations such as Glacier Peak or Mt. Stuart .
Ridge lift is plentiful in the Wenatchee area. The escarpments surrounding the Columbia River canyon form fantastic ridges with basalt lava columns rising hundreds of feet vertically, a spectacular sight when soaring along these ridges. The most popular ridge towards which most tows go are to the north and east of the airport, roughly two thousand feet above the airport elevation. The ridge rises gradually to the north from its low point of 2,800' MSL (about three miles east of the airport) to its high point near the summit of Badger mountain at about 4,200', along a winding path about 20 mile long. This ridge "works" with a remarkable range of wind directions, starting counterclockwise from 330° along its northern portion, from 300° to 200° along most of its length, and in its most southern section even with southeast winds up to 120°. On strong windy days the effect of the ridge extends well over 1,500' above the ridge.
This specifically local phenomenon deserves a special chapter. It enables soaring at Wenatchee on stable and calm days, when no one elsewhere manages to "stay up". The basalt lava columns rising hundreds of feet vertically along the top of the eastern ridge face south and west, accumulating the sun rays and storing the heat. Eventually the temperature rises in them so high that thermals are triggered along a continuous path right above the lava columns. This lift can be used for a final glide when the day is "dying", or just for having fun when no one else can stay up.
Disclaimer: this information has not been confirmed recently. Pilots are responsible for making sure they have current information!
For the skilled and prepared soaring pilot, wave lift provides the means for incredible altitude gains (the record stands at 50,671 feet); far above those attainable in a typical piston-powered aircraft... and well above the altitudes allowed for Visual Flight Rules! Fortunately there is a legal way for soaring pilots to access these heights.
Letter of Agreement
The Seattle Glider Council and the Columbia Basin Soaring Association, in cooperation with the Seattle ARTCC, have established several glider wave window areas in Washington State. A copy of the Letter Of Agreement with ARTCC may be found here (PDF format, revised in 2003). A map of the various wave windows may be found here (PDF format, revised in 2009).
To operate under this agreement you must be a member of the Seattle Glider Council or the Columbia Basin Soaring Association. Alternatively, SGC or CBSA may, at their discretion, allow you to file a signed statement with them establishing that you accept and will comply with all conditions of the Letter of Agreement.
How can I prepare? It is highly recommended that a pilot wishing to fly in the wave attend a High Altitude Chamber Class to - under very carefully controlled conditions - experience the effect of being at high altitude without supplemental oxygen, briefly experience hypoxia, his/her own reactions to it, and learns the techniques of how to manage breathing at high altitude. Pilots must be
Where is it?
Wave occurs in the Wenatchee area quite frequently, often directly over the airport. The best locations where you are likely to find it are 9 miles southwest of Pangborn airport and/or 10 miles north-northwest of the airport (over the Jumpoff Ridge and Rocky Reach Dam respectively). Due to many ridges in the area you can find waves elsewhere and not always in the same locations, which makes wave soaring around here very interesting and never boring.
How can I get that diamond?
Unlike in other parts of the U.S. where one has to tow high to get into the wave, at Wenatchee you can get your diamond right off the local ridge! Plus it is safer for you won't have to climb that high for your 5 kilometer gain. A good tactic is to descend as low as you can to sustain in ridge lift to notch the barograph (to descend below 3,000' MSL is relatively easy along the ridge east of Pangborn). When you then add the required 16,400' (=5,000 meters), you don't even need to get above 20,000'. The Diamond is yours! Of course, you have to find the wave once you climb up from the ridge, usually using thermals that drift you downwind. In a series of upwind dashes, each time ending up higher, eventually you connect. Once the altimeter starts spinning, it's the time for oxygen and the clearance into Class A airspace.
Process for opening a wave window:
The agreement "requires" that the Military Operations Specialist (MOS) at the Seattle Center be "notified" at least one hour prior to any "request" for usage of the Wave Window to allow the area to be cleared of normal aircraft use. The ATC Sector Controller may entertain this initial response on frequency at his discretion, but we should plan to make the initial call by telephone whenever possible. Phone # is (253)351-3523. This advance warning to ATC should be done if the day looks good or, if the day is changeable, when requested by an airborne pilot. Notification should only be made when there is a strong likelihood that wave exists and the window can be reached. Do not make the starting time any earlier than we expect to use it. The Sector Controller may advise that only a partial opening will be permitted or that they will not issue a clearance.
Request for Clearance
A request for clearance by the first pilot at approximately 17,500' will effectively open the window for the rest of us. That call is made to the Seattle Center on 126.1 MHz. However, every pilot/sailplane wishing to fly above FL 180 must obtain clearance from the Controller.
The Controller will most likely issue a clearance in response to your request. You and all other sailplanes subsequently operating in the "Window" are then subject to the terms of the Letter of Agreement, as amended, and the flight clearance. This may include altitude and time limits. After passing through 18,000', note altimeter setting, then change to 29.92 inches. Advise Center when transferring back and forth from 123.3 MHz. All pilots must advise Center as they leave the window. (Change altimeter back to original setting.) At least one sailplane should remain on the Center frequency, if possible, and advise Center when the last sailplane has left the window, so the airspace can be returned to normal usage. This call must be confirmed to Center by telephone as soon as possible afterwards that all pilots are out of the window, as they keep a tally count.
Wenatchee Wave Locations
In the immediate Wenatchee area there are two nearby windows, AREA TWO ("Wenatchee Wave Window") and the newer AREA FOUR ("Ellensburg Wave Window").
Wenatchee Wave Window:
ATC refers to this as AREA TWO; it includes altitudes from 18,000' to 23,000'. Contact ATC on 126.1 MHz. It is a rectangle defined by the coordinates:
Ellensburg Wave Window:
ATC refers to this as AREA FOUR; it includes altitudes from 18,000' to 45,000'. Contact ATC on 126.1 MHz. This window is a polygon defined by the coordinates:
Rattlesnake Hills Wave Window:
The Rattlesnake Hills region has two wave windows. ATC refers to these as AREA 3A and AREA 3B; they include altitudes from 18,000' to 45,000'. These windows are south of the new Ellensburg window and defined as follows:
Mt. Rainier Wave Window:
ATC refers to this as AREA ONE; in includes altitudes from 18,000' to 45,000'. Contact ATC on 126.6 MHz. The Mt. Rainier wave window is defined as follows: