Here at Dillingham Airfield, the trade winds blow against the mountain and are pushed up, creating updrafts all along the side of the mountain. Another kind of updraft or lift, we often get, is thermals. Thermals are columns of warm air rising off the ground. If you have ever seen hawks or even buzzards circling without flapping their wings, they are thermalling. They are hitching a free ride by circling in a thermal and letting it carry them upward. And there are two other kinds of lift. Convergence lift is like a mini front. Two air masses meet, and the colder and denser air pushes the warmer and lighter air up. Mountain waves form when air blows over a mountain range, setting up a series of stationary waves that extend away from the mountain. It’s similar to water flowing over a log in a stream. A series of waves form downstream from the log. The waves stay in the same place behind the log while the water flows through them.