OBS Weather & Hazardous Conditions 2 — Questions and Answers
Question 1: Which cloud formation is most commonly associated with sudden, violent thunderstorms on the water?
- Cirrus
- Cumulonimbus (Correct answer)
- Stratus
- Altocumulus
Correct answer: Cumulonimbus
Cumulonimbus clouds are tall, anvil-shaped storm clouds that produce lightning, heavy rain, and strong gusty winds.
Question 2: What does a rapidly falling barometer reading indicate for boaters?
- Improving weather ahead
- Stable conditions
- Approaching storm or bad weather (Correct answer)
- Fog is likely
Correct answer: Approaching storm or bad weather
A rapidly falling barometer means atmospheric pressure is dropping, which signals an approaching storm or deteriorating weather conditions.
Question 3: When caught in a thunderstorm on a small open boat, what is the safest position for passengers?
- Stand on the bow to watch the storm
- Sit low in the boat away from metal objects (Correct answer)
- Climb onto the cabin roof for visibility
- Move to the stern near the motor
Correct answer: Sit low in the boat away from metal objects
Sitting low in the boat and away from metal objects reduces the risk of lightning strike and keeps the center of gravity low in rough water.
Question 4: What wind speed (in knots) typically signals small craft advisory conditions?
- 5–10 knots
- 15–20 knots
- 21–33 knots (Correct answer)
- 34–47 knots
Correct answer: 21–33 knots
Small craft advisories are issued when sustained winds of 21–33 knots or hazardous wave conditions are expected.
Question 5: If you see lightning strike the water nearby while boating, what is the immediate risk besides fire?
- Sudden fog formation
- Electric shock through the water (Correct answer)
- Engine stalling from electromagnetic pulse
- Compass deviation
Correct answer: Electric shock through the water
Lightning can travel through water and electrocute anyone in or near the water, making it extremely dangerous to be overboard during a storm.
Question 6: What is the safest action when fog reduces visibility to near zero on open water?
- Increase speed to exit the fog bank quickly
- Turn on cabin lights and maintain course
- Slow down, post a lookout, and sound fog signals (Correct answer)
- Anchor immediately and wait for the fog to lift
Correct answer: Slow down, post a lookout, and sound fog signals
Slowing down, posting a lookout, and sounding proper fog signals reduces collision risk and complies with Navigation Rules.
Question 7: Which type of current hazard is most dangerous because it is invisible from the surface and can trap swimmers near a boat?
- Rip current
- Longshore current
- Hydraulic current near a dam (Correct answer)
- Tidal current
Correct answer: Hydraulic current near a dam
Hydraulic currents below low-head dams recirculate continuously, trapping people underwater in a deadly cycle called a 'drowning machine.'
OBS Weather & Hazardous Conditions 2
Which cloud formation is most commonly associated with sudden, violent thunderstorms on the water?