Stratus clouds have extensive horizontal layers and little or no vertical development. Which statement describes stratus clouds?

• A. Stratus have extensive horizontal layers, little or no vert. development.
• B. Stratus have extensive vertical development.
• C. Stratus form tall cumulonimbus.
• D. Stratus are always clear at night.

Answer: (A)

Stratus clouds are low, horizontally extensive cloud decks that form a uniform, sheet-like layer across the sky. This happens when air is relatively stable and moisture spreads out to create a wide, flat cloud cover rather than towers of rising air. That makes their defining feature a broad horizontal extent with little vertical growth, which directly matches the statement describing them as having extensive horizontal layers and minimal vertical development.

They don’t develop tall columns or reach high into the atmosphere; that would describe cumulus or cumulonimbus clouds. And while stratus can produce overcast skies (and sometimes fog at ground level), they are not something that guarantees clear skies at night.