What are ice crystals?

Ice crystals refer specifically to unbranched ice needles, columns, or plates that form and fall from clear skies. They are a result of the atmospheric conditions where supercooled water vapor freezes directly into ice without going through the liquid phase, leading to their distinct shapes.

These ice crystals can occur in various forms, such as needle-like structures or flat plates, and are often seen in very cold conditions where the air is not saturated with moisture. When conditions are right, they contribute to the phenomenon of winter precipitation, providing a unique texture and beauty to the environment during snowfall.

The other types of precipitation mentioned in the other choices do not accurately describe ice crystals. For instance, soft, fluffy snowflakes are typically made of numerous ice crystals that have aggregated together, rather than a specific form of ice crystal. Similarly, pellets of ice that fall during thunderstorms indicate a process involving melting and refreezing known as hail, rather than the straightforward formation of ice crystals. Lastly, small particles formed from melting snow describe a different process entirely, as they imply a change from solid to liquid and back again, which does not pertain to the crystalline structures of ice in stable atmospheric conditions.