Boating License Practice Test 2025 - Free Boating Exam Practice Questions and Study Guide

The common early sign of an approaching thunderstorm is a buildup of dark clouds. When conditions are right for a thunderstorm, the atmosphere begins to destabilize, leading to the formation of cumulonimbus clouds, which are characterized by their towering structure and dark appearance. These dark clouds indicate that significant weather changes are imminent, potentially including heavy precipitation, strong winds, and lightning. It is important for boaters and outdoor enthusiasts to recognize this sign, as the appearance of dark clouds can signal the need to seek shelter or prepare for worsening conditions.

In contrast, strong winds may accompany thunderstorms but are often a result of the storm itself rather than a sign of its approach. Bright sunshine typically indicates stable weather conditions, which are not associated with the onset of thunderstorms. While heavy rain can occur during or after a thunderstorm, it is not a sign of the storm's approach; rather, it usually occurs once the storm is already present. Understanding these signs helps individuals take preventive actions to ensure safety during stormy weather.