Why Does It Hail?

What You'll Learn

• Hail forms inside tall thunderstorm clouds called cumulonimbus clouds
• Updrafts push rain droplets high into freezing cold air, turning them to ice
• The ice balls grow as more water freezes onto them — like rolling a snowball
• When the hail gets too heavy, it falls to the ground
• Hail can be as small as a pea or as big as a baseball!

Words to Know

Hail

Balls of ice that fall from the sky during a storm

"Hail bounced off the car roof."

Updraft

A strong wind that blows UP inside a storm cloud

"The updraft pushed ice back up."

Cumulonimbus

A giant, tall storm cloud

"Cumulonimbus clouds make hail."

Freezing

When something gets so cold it turns solid

"The top of the cloud is freezing."

Check What You Learned

Fun Facts

• Hail forms inside cumulonimbus clouds, reaching 10+ miles high

  Source: NWS

• Cloud tops can reach -60F even in summer

  Source: NOAA

• Updrafts can reach 100+ mph

  Source: National Severe Storms Laboratory

• Each up-down trip adds an ice layer, creating visible rings

  Source: American Meteorological Society

• Hailstones fall when too heavy for updraft

  Source: NOAA

• Largest US hailstone: 8 inches, Vivian SD, July 2010

  Source: NOAA/NWS