How deep must fast-moving water be to potentially knock a person off their feet?

Fast-moving water can exert a significant force on a person, and even relatively shallow depths can be dangerous depending on the velocity of the water. Six inches of fast-moving water is often cited as the depth where a person can lose their footing and be knocked off balance. At this depth, the force generated by the movement of the water can overcome a person's weight and stability, especially if they are not braced or are caught off guard.

This depth is crucial for search and rescue personnel to understand, as it can inform their decision-making when navigating through water during operations. In scenarios involving swift currents or flash floods, even individuals who are physically fit may struggle to maintain their balance in water that is six inches deep or more, particularly if it is flowing rapidly. Therefore, maintaining a cautious approach in such conditions is vital for safety and effective rescue efforts.