Which statement correctly describes how an occluded front forms?

Which statement correctly describes how an occluded front forms?

• A. A warm front overtaking a cold front
• B. A stationary front separating two air masses
• C. A dry air mass wrapping around a moist air mass
• D. A cold front overtaking a warm front

Answer: (D)

Occluded fronts form when a cold front catches up to and overtakes a warm front in a mid-latitude storm. The advancing cold air is denser and slides beneath the warm air, lifting it off the surface. As the cold front overtakes, the boundary becomes a single front where cool air undercuts warm air, creating the occluded front. This is the scenario described by a cold front overtaking a warm front. The other descriptions don’t produce an occlusion: a warm front overtaking a cold front is a different interaction, a stationary front means the fronts aren’t moving relative to each other, and wrapping dry air around moist air isn’t how occlusion is formed.

Occluded fronts form when a cold front catches up to and overtakes a warm front in a mid-latitude storm. The advancing cold air is denser and slides beneath the warm air, lifting it off the surface. As the cold front overtakes, the boundary becomes a single front where cool air undercuts warm air, creating the occluded front. This is the scenario described by a cold front overtaking a warm front. The other descriptions don’t produce an occlusion: a warm front overtaking a cold front is a different interaction, a stationary front means the fronts aren’t moving relative to each other, and wrapping dry air around moist air isn’t how occlusion is formed.