During which condition is a lifeguard least likely to miss a drowning incident?

A lifeguard is least likely to miss a drowning incident when actively scanning the water. Active scanning involves a focused and systematic observation of the swimming area, which ensures that the lifeguard is attentive to the movements and behaviors of swimmers. This practice emphasizes not just looking at the water but also looking for signs that someone may be struggling, such as unusual splashing, a swimmer’s head going underwater without resurfacing, or a swimmer who appears to be in distress.

In contrast, other conditions—such as crowded areas with many distractions, poor visibility in the water, or even calm weather—diminish a lifeguard's ability to effectively notice distress signals. Crowded areas may create a chaotic environment that can distract a lifeguard, making it easier to overlook someone in trouble. Poor water visibility makes it difficult to see what's happening under the surface, while calm weather might lead to complacency, reducing the vigilance needed for effective monitoring. Therefore, active scanning is essential for ensuring that drowning incidents are caught in an effective and timely manner.