What hand signal indicates a need for assistance at night?

The hand signal that indicates a need for assistance at night is a blue strobe. This is widely recognized as a universal distress signal in various emergency response protocols, particularly in maritime contexts. The blue strobe light is effective in low-light conditions, making it easily visible to search and rescue teams or passing vessels. The use of bright, distinguishable colors during nighttime operations is crucial for ensuring that help is both noticed and quickly directed toward the individual in distress.

While other options might have specific uses or benefits under different circumstances, they do not serve as universally accepted signals for distress at night. For instance, a red flare is often associated with fire or warning rather than specifically requesting assistance, and might not be recognized as a call for help in the same way. Similarly, a green signal light is typically associated with safe passage or consent rather than a need for help, and a white flashlight, while visible, does not convey urgency or specific distress as effectively as a blue strobe.