Weather & Hazardous Conditions Flashcards

What is the primary danger of operating a boat near a low-head dam?

Answer: A recirculating hydraulic that can trap and drown people

Low-head dams create a continuous recirculating hydraulic current on the downstream face that traps and holds victims underwater.

At what water temperature does cold water immersion become immediately life-threatening due to cold shock?

Answer: Below 60°F (15°C)

Cold shock begins at water temperatures below 60°F (15°C), causing gasping, hyperventilation, and potential cardiac arrest within minutes of immersion.

When boating in fog, how often must a powerboat under way sound its fog signal?

Answer: Every 2 minutes

Navigation Rules require a power-driven vessel underway in restricted visibility to sound one prolonged blast at intervals of not more than 2 minutes.

Which wave condition poses the greatest capsizing risk to a small boat?

Answer: Short, steep breaking waves on the beam

Short, steep breaking waves striking the side (beam) of a boat can roll it over before the operator can react, making beam seas especially dangerous.

What is 'white water' on a river, and what does it signal to a boater?

Answer: Aerated water indicating turbulence, rocks, or rapids

White water is caused by air mixing with water over rocks or rapids, signaling turbulent, potentially dangerous shallow hazards ahead.

Which action best protects boaters from hypothermia after an unexpected capsize in cold water?

Answer: Adopt the HELP position (Heat Escape Lessening Posture) and stay still

The HELP position — knees drawn to chest with arms hugging the body — reduces heat loss from the core and can extend survival time significantly.

What does a 'storm warning' flag display (two red pennants with black squares) signal at a marina?

Answer: Storm warning with winds 48–63 knots expected

Two red pennants with black centers (storm warning flags) are displayed when winds of 48–63 knots are forecast, warning boaters to stay in port.