Convergence zone lift can at times be somewhat turbulent, especially if air from different sources is mixing, such as along a sea-breeze front. The general roughness may be the only clue of being along some sort of convergence line. There can also be narrow and rough (but strong) thermals within the convergence line. Work these areas like any other difficult thermals, using steeper bank angles and more speed for maneuverability. 

## Combined Sources of Updrafts 

Finally, lift sources have been categorized into four types: thermal, slope, wave, and convergence. Often, more than one type of lift exists at the same time, such as thermals with slope lift, thermaling into a wave, convergence zones enhancing thermals, thermal waves, and wave and slope lift. In mountainous terrain, it is possible for all four lift types to exist on a single day. The glider pilot needs to remain mentally nimble to take advantage of various types and locations of rising air during the flight. 

Nature does not know that it must only produce rising air based on these four lift categories. Sources of lift that do not fit one of the four lift types discussed probably exist. For instance, there have been a few reports of pilots soaring in travelling waves, the source of which was not known. At some soaring sites, it is sometimes difficult to classify the type of lift. This should not be a problem. Simply work the mystery lift as needed, then ponder its nature after the flight. 

