🔍 Key Concepts

• Steam fog forms when very cold air moves over much warmer water, causing water vapor to evaporate and then condense just above the surface. • Know the differences between radiation fog, advection fog, and steam fog and what temperature relationships cause each. • Think about river conditions on the Mississippi and Ohio Rivers in fall and winter, especially when cold air masses move over relatively warm river water.

💭 Think About

• Which choice describes a situation where the water is warmer than the air above it, so that moisture can evaporate and then quickly condense into fog? • Look at the options that mention air moving over water. For each one, ask: is the air warmer or colder than the water, and what type of fog is usually linked with that setup? • Try to recall or sketch a simple diagram: cold air arrow over warm water vs warm air arrow over cold water. Which one would create a fog that looks like steam rising from the water surface?

✅ Before You Answer

• Identify which answer choice clearly has colder air over warmer water. • Eliminate choices that mainly describe radiation fog (from ground cooling at night) or frontal/precipitation fog (rain from warm air into cold air). • Before picking, say out loud: "In steam fog, the water is the heat source, and the air is colder" and see which option matches that picture.