What does a thumbs down signal mean when skiing?

A thumbs down signal when skiing universally indicates that a skier should slow down. This gesture is a clear and easily recognizable form of communication among skiers. It helps convey the need for a decrease in speed, which can be crucial for safety on the slopes, especially in situations where a skier may need to navigate around obstacles, other skiers, or transition to a less steep area. Maintaining control at an appropriate speed is essential for both the skier's safety and the safety of others nearby.

In contrast to the other options, such as speeding up, turning, or diving under water, which do not correlate with this specific gesture, the thumbs down signal clearly conveys the intent to reduce speed, making it an important signal for effective communication on the slopes.