When may hazardous wind shear be expected?

• A. Only in clear air away from clouds
• B. In areas of low level temperature inversion
• C. During strong downdrafts
• D. Only near warm fronts

Answer: (B)

Wind shear is a rapid change in wind speed and/or direction with height, and that can catch a glider off guard by changing the airspeed or path you’re flying through. When a low-level temperature inversion forms, the air near the surface is strongly stable and little mixing occurs. The surface air is slowed by friction and cooled, while the air above the inversion top can be moving differently or faster. This creates a very sharp change in wind over a relatively short vertical distance right at the inversion layer. As you climb through or descend through that boundary, you can encounter sudden gusts or a noticeable shift in wind, which is hazardous for supporting lift and control in a glider. That’s why hazardous wind shear is associated with areas of low-level temperature inversion.