Under what surface temperature condition do ice pellets form?

• A. The temperature must be below freezing for ice pellets to form.
• B. Ice pellets form at any temperature above freezing.
• C. Ice pellets form only in rainstorms.
• D. They are not temperature dependent.

Answer: (A)

Ice pellets form when the surface is cold enough—below freezing—for the falling precipitation to refreeze before or as it reaches the ground. When the surface temperature is below 0°C, melted drops aloft can refreeze in the cold layer near the surface, producing small ice pellets (sleet) that survive to the ground. If the surface is at or above freezing, those pellets would melt on contact and you’d see rain instead. The other options misstate the role of surface temperature or when such pellets can form.