Maritime Weather and Oceanography Flashcards
7 cards from real Coast Guard Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Maritime Weather and Oceanography flashcards as text
What causes radiation fog most commonly found in harbors and estuaries during early morning hours?
Answer: Nocturnal radiative cooling of land and the air just above it
Radiation fog forms when land radiates heat at night, cooling the surface air to its dew point; it is common in sheltered bays and rivers after clear, calm nights.
A tropical cyclone is officially classified as a hurricane when its sustained winds reach at least:
Answer: 64 knots (74 mph)
A tropical cyclone reaches hurricane status when its maximum sustained surface winds reach 64 knots (74 mph, Category 1 on the Saffir-Simpson scale).
The Coriolis effect causes freely moving air and water in the Northern Hemisphere to deflect:
Answer: To the right
Earth's rotation causes the Coriolis effect, which deflects moving objects (air, ocean currents) to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
A waterspout differs from a land tornado primarily because it:
Answer: Forms over a body of water and can be dangerous to small craft
A waterspout is a rotating column of air over water and, while often weaker than land tornadoes, can be extremely hazardous to small vessels, requiring immediate evasive action.
Which VHF-FM channels broadcast continuous NOAA Weather Radio marine forecasts in U.S. coastal waters?
Answer: Channels WX1, WX2, or WX3 (NOAA Weather Radio)
NOAA Weather Radio broadcasts on weather channels WX1 (162.550 MHz), WX2 (162.400 MHz), and WX3 (162.475 MHz), providing continuous marine weather forecasts and warnings.
Ocean surface currents are primarily driven by:
Answer: Wind stress on the ocean surface and density-driven thermohaline circulation
Surface ocean currents are primarily driven by prevailing winds (wind-driven circulation) while deeper thermohaline circulation is driven by temperature and salinity differences that create density gradients.
When operating in reduced visibility due to fog, U.S. Coast Guard Rules of the Road require vessels to proceed at:
Answer: A safe speed appropriate for conditions, with readiness to stop
COLREGS Rule 19 requires every vessel in restricted visibility to proceed at a safe speed adapted to the prevailing conditions, with engines ready for immediate maneuver.