Prudence Libby, age 9, of Scarborough, Maine, for her question:
Why does icy hail fall in the summer?
Rain, snow, and hail are made in the air high, high above our heads. The Weather a mile or two upstairs is often very different from the weather down on the ground. On a summer’s day, the ground may be scorching hot, while high up in the air the clouds are shivering with freezing cold.
Most of the moisture from the clouds falls down as silvery raindrops of pure, plain water. When the air is chilly, the moisture may form dainty snowflakes, which are made from tiny fragments of ice. This does not surprise us, because WE know that when the air gets cold enough, liquid water turns to solid ice. And snowflakes flutter dawn only when the winter weather is chilly.
But it is quite plain that hailstones are also made of ice. If you hold one in your warm hand it soon melts into liquid water. And hailstones sometimes come pelting down from a sweltering summer sky. They do not fall as often as rain, because the Weather conditions have to be just right before the misty clouds can be changed into bullets of icy hail.
Weather conditions begin at the ground and reach six or seven miles above our heads. There are warm layers and cool layers of this upstairs air stacked one upon another. There are dry layers and damp layers. Near the ground the breezes may be blowing from the West, while upstairs a windy breeze may be blowing from the East.
On a summer’s day, hail may fall from a stormy thunderhead. And up in this huge cloud the weather conditions are very wild indeed. Fierce winds blow around and up and dawn. There are warm drafts and hot drafts. The cloudy moisture is whisked around and becomes raindrops. Some of the raindrops are swept up again and again into freezing spots. They freeze into bullets of icy hail and at last come pelting down to the ground.
As a rule, a hailstone is a tiny Pellet much smaller than a Pea. But sometimes hailstones bigger than marbles come pelting down. If we cut open a hailstone, WE find that it is made of layers like the skins of an onion. Some of its icy jackets are hard and frosty white, and some of them are soft, soggy mush.