Certified Flight Instructor (CFI) Practice Exam

What does the METAR code "SG" specifically refer to?

1. Snow Grains

2. Snow Showers

3. Ice Grains

4. Fog Grains

The correct answer is: Snow Grains

The METAR code "SG" specifically refers to Snow Grains, which are small, white, opaque grains of ice that resemble snow pellets but are much smaller. They typically fall from stratus clouds and are associated with light precipitation. Snow grains are distinguished from other types of snow because they have a different size and structure, often resulting from supercooled water droplets freezing onto ice nuclei. Understanding this terminology is crucial for pilots and meteorologists, as it helps in accurately interpreting weather conditions affecting flight safety. Snow grains can reduce visibility, but they usually do not accumulate significantly on the ground, which differentiates them from heavier forms of snowfall. Awareness of this distinction enhances situational awareness in flight operations.