What storm warning signal requires one red light over a white light at night?

The correct answer is small craft warning because this signal is specifically represented by one red light over a white light at night. In maritime communication, the use of colored lights helps convey crucial information about weather conditions to sailors and boaters. A small craft warning alerts operators of smaller vessels about potentially hazardous weather conditions that could affect their safety at sea, primarily when wind speeds reach a certain threshold.

The other types of warnings mentioned have different signaling systems: gale warnings, hurricane warnings, and tornado warnings all signify more severe weather conditions and are represented using different light or flag combinations. Understanding these signals is essential for ensuring safety on the water, as they provide vital information about the weather that could impact navigation and vessel operation.