what causes hailstones

Hailstones form inside strong thunderstorm clouds when powerful updrafts lift raindrops high into very cold air, where they freeze and grow layer by layer as they collide with more supercooled water droplets. They usually keep growing until they become too heavy for the storm’s updrafts to hold up, then they fall to the ground as hail.

How it happens

• Warm, moist air rises fast in a thunderstorm, creating strong updrafts.

• Water droplets get carried above the freezing level and turn into supercooled droplets or ice embryos.

• More droplets freeze onto the ice core, building a hailstone in repeated layers.

• When the stone gets heavy enough, gravity wins and it drops as hail.

Why some hail gets big

• Stronger updrafts can keep hailstones suspended longer, letting them collect more ice.

• Severe rotating storms, especially supercells, are more likely to produce large hail.

• The hailstone’s path through the storm affects how much time it has to grow.

Simple picture

Think of a hailstone like a snowball being rolled around inside a storm cloud, except the “snow” is layers of frozen water from supercooled droplets.

Bottom line

Hail is basically storm-made ice, built by repeated freezing inside tall, violent thunderclouds.