When does a dynamic stall occur for a parachutist?

A dynamic stall occurs at the end of a flare when a parachutist rocks back under the canopy. This situation typically arises when a parachutist initiates a flare to slow down their descent just prior to landing. As the parachutist pitches back, the angle of attack on the parachute increases beyond its critical angle, leading to a dynamic stall. This stall can cause a sudden loss of lift, which is why timing and technique during the flare are crucial for successfully managing the descent and ensuring a smooth landing.

While free fall, deployment, and hard landing scenarios also involve critical aerodynamic principles and challenges, they do not directly relate to the specific condition of dynamic stall as understood in the context of parachuting. During free fall, parachutists experience stable aerodynamic forces. During deployment, a parachute opens and generates lift without reaching the critical angle of attack required for a stall. In a hard landing, while there may be high forces involved, it is not the same phenomenon as a dynamic stall initiated by increased angle of attack in the flare.