What is a squall?

A squall is defined as a sudden and brief increase in wind speed, often accompanied by changes in weather conditions such as rain or thunderstorms. This phenomenon typically occurs when cold air rapidly moves into a region, displacing warmer air and creating instability in the atmosphere. The characteristic nature of a squall is that it is both sudden and temporary, leading to a notable increase in wind speed over a short period. This can pose significant challenges and hazards for sailors due to the potential for sudden changes in weather conditions and wind patterns, making it crucial for mariners to be aware of squall predictions.

In contrast, the other options describe different concepts. The description of a sailing maneuver is unrelated to the meteorological definition, a prolonged storm at sea does not capture the brief nature of a squall, and a weather condition signifying clear skies does not correlate with the presence of increased wind speeds or rain that typically defines a squall. Thus, option B accurately encapsulates the essential characteristics of a squall in weather terms.