Final answer:
The main difference between sleet and hail is that sleet starts frozen then melts as it falls while hail starts as rain and then freezes as it falls.
Step-by-step explanation:
The main difference between sleet and hail is that sleet starts frozen then melts as it falls while hail starts as rain and then freezes as it falls. In the case of sleet, the precipitation passes through a layer of warm air and melts before re-freezing into ice pellets as it reaches the ground. On the other hand, hail forms in severe thunderstorms when strong updrafts carry raindrops upward, where they freeze and grow in layers as they are repeatedly lifted and frozen by the storm's updrafts.
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