Ice pellets

Ice pellets are small balls of ice.

They look clear and hard. They fall from the sky.

Snow falls through warm air. This makes the snow melt. Then the snow falls into cold air. The melted snow turns back into ice.

These ice balls can bounce. They make a loud tap sound. This is different from soft rain.

Ice pellets are heavy. They are harder to clear than snow. They also take a long time to melt. It is fun to watch them fall.

Ice pellets are small, hard balls of ice.

They are clear and can be seen through. In the United States, people call them sleet. In other places, sleet means a mix of rain and snow.

These pellets form in a special way. First, snowflakes fall through a layer of warm air. This warm air is above freezing. The warmth melts the snow. Then, the melted snow falls into a cold layer of air. This cold layer is near the ground. The water re-freezes into ice pellets.

If the cold layer is too thin, the water stays liquid. This creates freezing rain instead.

Ice pellets make a loud "tap" sound when they hit things. They bounce on the ground. They are different from soft hail. They are also different from slushy snow.

Ice pellets are very heavy. They are harder to clear than snow. They also take a long time to melt.

Ice pellets are small and hard balls of ice.

They are clear enough to see through. These pellets are not the same as graupel. Graupel is a soft hail made of white, cloudy rime. Ice pellets are also different from a mix of rain and snow. That mixture is often a slushy liquid. Ice pellets often bounce when they hit the ground. They make a high "tap" sound on a jacket or a windshield. This is different from the dull splat of a raindrop.

These pellets form through a specific way it works in the sky.

First, snowflakes fall through a layer of warm air. This warm air is above the freezing point. The warmth causes the snow to melt partially or completely. Next, the melted water falls into a layer of freezing air. This cold layer is located closer to the ground. The water re-freezes into hard ice pellets before it hits the surface. If the cold layer is too thin, the water stays liquid. This results in freezing rain instead of pellets.

Different places use different names for this weather.

In the United States, the official term is sleet. The U.S. National Weather Service uses this name. However, people in many Commonwealth countries use the word differently. In Canada, sleet usually means a mix of rain and snow. Because of this, Environment Canada does not use the word sleet. They use the terms "ice pellets" or "wet snow" instead. This helps avoid confusion between different types of weather.

Weather experts use special codes to track these events.

The METAR code for ice pellets is PL. Before November 1998, the code was PE. These pellets often appear near a warm front. They can also appear behind a cold front. Sometimes they happen with a stationary front. In the eastern United States, warm air can flow north from the Gulf of Mexico. This air can move over cold air for hundreds of miles. This can lead to large amounts of ice pellets.

Ice pellets can be harder to deal with than snow.

If you have the same amount of ice pellets as snow, the ice is heavier. This makes it more difficult to clear away. Ice pellets also take a long time to melt. They have less surface area than fresh snowfall. This means they stay frozen longer than snow does. You can see how small they are by looking at a U.S. penny.

A penny is about 19.05 mm wide.

Ice pellets are a specific form of precipitation. They consist of small, hard, and translucent balls of ice.

While they may look like other frozen weather, they are distinct. They are not the same as graupel, which is a soft hail made of opaque rime. They are also different from a slushy mixture of rain and snow. Unlike liquid raindrops that make a dull splat, ice pellets often bounce. When they strike objects like windshields or dried leaves, they make a high-pitched "tap."

The formation of ice pellets requires a very specific temperature profile in the atmosphere.

This process begins with snowflakes falling from a cold layer high in the sky. As they fall, they encounter a layer of air that is above the freezing point. This warm layer causes the snowflakes to melt partially or completely. In French, this is called neige fondue, which literally means "melted snow." After melting, the water continues to fall toward the ground. It then enters a second sub-freezing layer of air located near the surface. This cold layer causes the water to re-freeze into hard pellets before it hits the ground.

The thickness of this bottom cold layer is very important for the type of weather produced. If the sub-freezing layer is deep enough, the water has time to become solid ice pellets. However, if the cold layer is too small, the water will not have time to re-freeze. In that case, the precipitation becomes freezing rain instead. This rain stays liquid until it hits a surface, where it then freezes.

These temperature patterns are most common in front of a warm front during the cold season. They can also appear behind a cold front or near a stationary front.

Terminology for this weather varies depending on where you live in the world. In the United States, the official term used by the National Weather Service is sleet. However, the word sleet has a different meaning in many Commonwealth countries, such as Canada. In those places, sleet usually describes a mixture of rain and snow. Because of this confusion, Environment Canada avoids the word sleet entirely. Instead, they use the specific terms "ice pellets" or "wet snow." Weather experts also use the METAR code PL to identify ice pellets, though the code was PE before November 1998.

In most parts of the world, ice pellets occur for only brief periods. They usually do not accumulate in large or troublesome amounts. However, there are notable exceptions in certain geographic regions. In the eastern United States and southeastern Canada, large accumulations can happen. This occurs when warm air flows north from the Gulf of Mexico. This warm air can overrun cold, dense air at the surface for many hundreds of miles. When this happens for an extended period, significant amounts of ice pellets can build up.

Dealing with an accumulation of ice pellets is different from dealing with snow.

If you have the same volume of ice pellets as you do snow, the pellets are much heavier. This extra weight makes the ice more difficult to clear away from roads or paths. Additionally, ice pellets take a much longer time to melt than fresh snowfall. This is because they have less surface area compared to the same volume of snow. Because they do not melt quickly, they can remain on the ground for a long time.

To understand the physical scale of these objects, we can compare them to common items.

For example, ice pellets are often very small when held next to a U.S. penny. A penny has a diameter of 19.05 mm. Seeing them next to such an object helps show how tiny and numerous they are. Understanding these small pieces of ice helps scientists and weather services predict how much weight will fall on structures and how long the ice will last. This connection between temperature layers and physical properties is a key part of studying weather systems.