Book 7, Question 36
Why Do Some Storms Make Hail the Size of Marbles?
Some thunderstorms make hail as big as marbles, or even bigger. That happens when the storm has very strong updrafts that keep ice floating high up for longer. The longer a hailstone stays up, the more icy layers it collects.
From the book
Page from A Million Whys Book 7
More fun facts
- Hail starts as raindrops carried up by a storm's updraft into very cold air, where they freeze.
- Hailstones grow when liquid water drops hit them and freeze onto their surface.
- Water that freezes instantly traps air bubbles and makes cloudy ice. Water that freezes slowly makes clear ice.
- Hail falls when it gets too heavy for the updraft to hold it up.
- Hail the size of a quarter, 1 inch across, or bigger is considered severe.
- The largest hailstone found in the United States fell in Vivian, South Dakota, in 2010. It was 8 inches across and weighed almost 2 pounds.
- Very large hailstones, more than 4 inches across, can fall faster than 100 miles per hour.
- Where Nebraska, Colorado, and Wyoming meet, an area called hail alley gets about 7 to 9 hail days a year.
Sources: NOAA
Questions kids ask
What is the biggest hailstone ever found in the U.S.?
It fell in Vivian, South Dakota, in 2010. It was 8 inches across.
Why are some hailstones cloudy and some clear?
Fast-freezing water traps air bubbles and looks cloudy. Slow-freezing water lets bubbles escape and looks clear.