FAA Sport Pilot Airplane (SPA)WeatherEasy
A pilot is briefed that a cloud layer at the departure airport is based at 4,500 feet AGL. According to the standard cloud classification system, which family does this cloud belong to?
- AClouds with extensive vertical development
- BMiddle clouds
- CLow clouds
- DHigh clouds
Show answer & explanationAnswer & explanation
Correct answer: C. Low clouds
Low clouds are generally based from the surface up to about 6,500 feet AGL and include stratus, stratocumulus, and nimbostratus. A base of 4,500 feet AGL falls within this low-cloud family.
Why the other options are wrong
- A. Vertical development clouds like cumulonimbus can span all levels but are classified separately by their growth, not base altitude alone.
- B. Middle clouds (alto family) are typically 6,500 to 20,000 feet.
- D. High clouds (cirrus family) are typically above 20,000 feet.
Cloud Classification by Altitude
Clouds are grouped into low, middle, high, and vertically developed families based on the altitude of their bases.
- Low clouds: surface to ~6,500 ft AGL (stratus, stratocumulus, nimbostratus)
- Middle clouds: ~6,500-20,000 ft (altostratus, altocumulus)
- High clouds: above ~20,000 ft (cirrus, cirrostratus, cirrocumulus)
- Vertical clouds: cumulus and cumulonimbus can span multiple levels
Memory trick: Low, Alto, Cirro — think Low House, Middle Apartment, High Tower.