Wind direction and strength are of primary importance when soaring in mountains, but changes in the degree of slope are significant too. Inconsistency in vertical profile can cause airflow to separate from the surface just as it does with roughness on the surface of a sailplane wing. A weakening of ‘orographic’ lift could suddenly draw you dangerously close to terrain directly below you at close range. The possible bright side: a place where upslope winds separate from the surface is exactly where thermals are most apt to do the same! Either way, whether you’re climbing by a change in slope or rushing by it horizontally, expect changes in lift rate – positive or negative – and feel for them.