What does one short whistle blast indicate?

A short whistle blast is typically used to gain the attention of guests in a lifeguarding context. This is an effective way for lifeguards to communicate with swimmers, ensuring they are aware of any important announcements, safety rules, or observations the lifeguard may want to convey. The use of the whistle helps to cut through noise and distractions at the pool or beach environment, allowing the lifeguard to communicate effectively without having to leave their station or direct approach toward each swimmer individually.

Other options indicate actions that are either more significant or require different types of communication, such as a longer whistle blast for emergencies or a series of signals for shifts in personnel, but the primary purpose of a short blast is to bring immediate attention in a non-alarming manner.