Shearlines present one of the more baffling soaring conditions – even for those who understand them. As with other forms of lift, in small or weak shears it’s sometimes necessary to remain in one area to stay aloft. Yet the lift can be so sporadic that continuous circling is impractical. A parcel of air that feels very thermal-like can suddenly fall still and begin to sink. Be ready at any moment to abandon a conventional thermal turn and fly toward the shear’s rising side. Where the shear is narrow, figure eights may be more effective, mixed with occasional full circles or straight runs. (If using a figure-eight, turn toward the livelier air at each end of your eight, just as when turning into the wind while ridge soaring.)
Shear lift can also bubble up cyclically, first in one spot, then in another, and later back where it was before. A sort of rhythm may exist, allowing you to anticipate and move away from one area before it weakens, arriving nearby just as newer lift begins to build.
Cloud formations caused by such action can be very short-lived, or could last all day. They usually help in finding lift, but if far above you they can be deceptive. Clouds can appear over an area that’s presently inactive at your altitude, while down where you are the lift might be not yet marked by cloud. Here too, a useful rhythm may be discernable.
Shear clouds can form at multiple levels in one localized area. Moving toward their forming edge may enable you to soar up, over their tops. You might be able to climb hundreds of feet above growing wisps while more float overhead. (This seems to occur more often over high terrain.)
The trick, whether holding station in an isolated patch of shear or running along a line that extends out of sight, is to remain within that interface where the merging of flows is most dynamic. A shear’s character can vary greatly as you travel along it, or as you or it change altitudes. Therefore, it’s good to employ multiple models interdependently, to visualize what’s actually happening, and be ready to alter your assessment and technique at any moment. Remember that, typically, the best lift will lie in a narrow interface between two distinct wind directions or wind strengths, and drifting in a crosswind toward the opposing wind can shorten a search for optimal lift. Feel and watch constantly for subtle – or not so subtle – changes. Respond immediately to differences in either the feel of the ambine air or our mental conception of physical conditions. Porpoise, veer off course as necessary to follow the shear, but stop to climb only when the lift is stronger than average or you need altitude.