Mark Jones, age 9, of Black Mountain, N.C., for his question:

HOW ARE HAILSTONES FORMED?

Hail is made of roundish, hard balls of ice that fall from the clouds during some thunderstorms. Hailstones form much as sleet does.

When small ice crystals or snowflakes contact supercooled water drops which are drops of water still liquid at temperatures below freezing they freeze instantly and form hail. Some unfrozen water remains attached to the growing hailstone until it freezes and some of it escapes. This process continues as long as the hailstone is in the region of the supercooled water.

The ball of ice is often caught in an updraft and carried back to the supercooled water region and there it again grows in size.

This up and down process can be repeated many times.

Finally the hailstone falls to the ground.