SkillBuilder discussion Communicating 1. How do hailstones grow larger inside the storm cloud? 2. What role do updrafts play in forming hailstones? 3. At what speed do hailstones fall to the Earth?
FIGURE7 How a supercell hailstorm forms
As the ice crystals rise and fall with the updrafts, they collide with water droplets that freeze around them, forming hailstones.
The more the hailstones rise and fall, the larger they become.
Hailstones fall to Earth (at speeds of around 160 km/h) when they become too heavy or are caught in a downdraft.
Hail begins to form when strong updrafts lift moist air into the freezing zone in cumulonimbus clouds. Here, the moisture in the air turns to ice crystals.
A supercell storm has extremely strong updrafts. These keep hailstones suspended longer than regular storms, allowing hailstones to grow bigger. To form cricket-ball sized hailstones, there must be updrafts of around 160 km/h.
FIGURE8 Powerful thunderstorms bring down trees.
FIGURE9 Thunderstorms may lead to potholes in roads.
320 Jacaranda Humanities Alive 7 Victorian Curriculum Third Edition
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