Fluffy white snowflakes flutter down from cold, grey winter skies. Silvery raindrops may spill down from warm summer clouds or from warm or coolish clouds of winter. Hailstones may pelt down from a winter storm or from a summer thunderhead. Sleet too may come tumbling down at any time of the year when the weather conditions in the sky are ,just right.
Some of the old timers say that sleet is a soggy mixture of rain and snow. But the weatherman says that sleet is a downpour of icy pellets. Sometimes it is hard for an ordinary person to tell the difference between hail and true sleet. What’s more, a downpour of this sleet is very rare, even more rare than a barrage of pelting hailstones.
The snow, rain, hail and sleet that tumble down from the clouds are all made from moisture in the air. But each is made by a different weather recipe. Each recipe depends upon different weather conditions such as warm or cool air, calm or moving air. We do not get very frequently dust the right weather conditions for turning the moisture of the air into sleet, which is why a downfall of sleet is so rare.
As a rule, the air near the ground is warmer than the air higher above our reads. The weatherman’s sleet begins to form when the air upstairs happens to be warmer than the air near the ground. The sleet begins to form in a dark cloud heavy with droplets of moisture. Millions of misty droplets gel together to form a raindrop, another and another. Soon a shower of raindrops starts to fall down through the warm air upstairs.
On the way, before they reach the ground, the drippy raindrops must fall through a layer of freezing cold air. And air that is cold enough to freeze water is cold enough to freeze the watery raindrops. First the drops
First the drops of water become freezing rain, which is colder than cold. This freezing rain may reach the ground. But sometimes it is turned into bumpy pellets of ice.
When this happens, little pellets of ice bounce onto the ground and we get a downpour of the weatherman's sleet: We may get these icy pellets in the fall, winter or spring and they may tumble down from the heart of a summer thunderhead. If you cut open a pellet of true hail, you will see that it is made from onion skin layers of ice. A pellet of sleet is a single wad of ice. The two are different because they are formed by different weather recipes.
Sometimes the freezing rain does not turn to ice until it touches a solid surface, But when these chilly drops reach the ground, they run together and freeze into solid sheets of ice. The trees and twigs and telegraph wires are suddenly dressed in glistening jackets of glassy ice and we get an ice shower. If the sun comes out, the whole world sparkles with frozen fire.