Why does it snow and not hail in winter?

Updrafts are sufficient to support enlarged hail embryos in the clouds. As the air flow rises and falls, it constantly merges with snowflakes and small water droplets along the way to form ice cubes with alternating layers of transparency and opacity, and when it increases to a certain extent and the updraft cannot support it, it falls to the ground, which is the principle of a hailstone.

In winter, the temperature on the ground is particularly low, and the water vapor condenses into white frost when it is cold on the ground, and does not form hail.

Hail is caused by severe convective weather, which generally occurs in summer, and convection is not active in winter, so hail cannot be formed. Whereas, snow is formed by the condensation of rain below freezing.

What does hail in the summer look like? It turns out that when the raindrops in the clouds encounter a violent rising air flow and are carried to a high altitude below 0, they liquefy into Xiaoice beads; When the airflow weakens, the Xiaoice beads fall; When the updraft containing water vapor increases again, the Xiaoice beads rise and increase again; Jumping up and down like this, the small Xiaoice beads may gradually become large hailstones and finally fall to the ground.

In winter, convective weather is weak, which is unfavorable for hail.

When the raindrops in the clouds meet a violent rising air flow and are carried to a high altitude below 0, they liquefy into Xiaoice droplets; When the airflow weakens, the Xiaoice beads fall; When the updraft containing water vapor increases again, the Xiaoice beads rise and increase again; Jumping up and down like this, the small Xiaoice beads may gradually become large hailstones and finally fall to the ground.

When there is a lot of water vapor near the ground and cold air, the water vapor will liquefy into small water droplets with the dust in the air as the core, which is called fog.

In summer, the ground is very hot and there is a lot of water vapor. When the temperature is low before dawn, water vapor condenses into dew on leaves, flowers and plants.

In the morning of winter, the temperature on the ground is particularly low, and the water vapor condenses into white frost on the ground when it is cold.

In winter, there is hail, but it is rare. Hail mostly occurs in spring and summer, and can also occur when the conditions are reached in winter, while snow only occurs in severe winter, the biggest difference between them is that hail formation requires violent updraft movement, while snow does not need it, only normal movement of rising water vapor; The relative humidity of hail should reach 100 percent, while snow does not need to wait. However, they still have a common feature, that is, they need a certain temperature difference, and they all need a certain amount of condensation nuclei.

Hail precautionsWhen hail strikes, pay attention to listen to the local weather forecast, understand the weather change trend, and prepare for hail; Pay attention to the weather conditions of the day, if the morning is cool and humid during the hail season, and the solar radiation is strong at noon, resulting in strong air convection, it is easy to develop into cumulonimbus clouds and form hail. Therefore, there is a saying that "the morning is cold and the head is broken in the afternoon", "the dew is heavy in the morning, and the hail is fierce after the sound".

When this kind of weather occurs, the elderly and children should not go out, and it is best to stay at home. Avoid it in time, there is a proverb cloud: "black cloud tail, yellow cloud head, hail kills sheep and cattle", you should be especially careful of this kind of weather.

In addition, when hail comes, it is necessary to quickly find a safe place with a cover and lightning protection to prevent hail from attacking.

Hail falls in the winter but is less common, most common in the summer or at the turn of spring and summer.

Hail, a solid precipitation. It is a spherical or conical ice cube composed of alternating transparent and opaque layers. The diameter is generally 5 50 mm, the large sometimes can reach more than 10 cm, also known as hail or hail block, commonly known as hail, some areas are called "cold seeds", summer or spring and summer are the most common.

Some are as small as mung beans and soybeans, as large as ice particles like chestnuts and eggs, and the extra-large hailstones are larger than grapefruits. Hail often destroys crops, threatens the safety of people and animals, and is a serious natural disaster. Many countries with severe hailstorms have conducted artificial hail prevention tests.

Hail falls in the winter but is less common, most common in the summer or at the turn of spring and summer.

There is an important condition for the birth of hail: the air layer is unstable, and the cold and warm air is "strong", so hail often appears in the summer when the weather is more variable, and the particles are relatively large and the most "hard".

Hail activity is not only related to the weather system, but also greatly affected by topography and landform. China has a vast territory, complex topography, and great differences in landforms, and China has the largest plateau in the world, which makes the atmospheric circulation complicated. Therefore, the hail weather in China has a large impact and a wide range of hail disasters.

Hail is a frequent occurrence in the summer, because the water vapor encounters strong convection of hot and cold in the air, forming hail, and this phenomenon is extremely rare in winter, and hail generally does not occur in winter, because the convection intensity of hail strength cannot be reached at high altitude. Most people only see something like hail, which is called freezing rain.

Because hail is formed for climatic reasons, hail generally occurs in winter.

Except for Guangdong, Hunan, Hubei, Fujian, Jiangxi and other provinces in China, which have fewer hailstorms, all parts of China are affected by hailstorms of varying degrees every year. Especially in the mountainous and hilly areas of the north, the terrain is complex, the weather is changeable, and there are many hailstorms, which are very harmful to agriculture.

In the hail cloud, the strong updraft carries many large and small water droplets and ice crystals, some of which combine with the ice crystals to freeze into larger ice particles, and these particles and supercooled water droplets are transported by the updraft to the water accumulation area, which can become the hail core, and the core of the initial growth of these hail has good growth conditions in the water content accumulation area.

At this time, the hail has grown, and the updraft there is weak, and when it cannot support the growing hail, the hail falls in the updraft, and in the fall, it continues to merge with ice crystals, snowflakes and water droplets and continue to grow.

Hail only occurs in summer when there is strong convection (a rapidly rising stream of watery air that forms ice crystals when cold at high altitudes and repeatedly moves in the air flow to form hail) weather. In winter, the sun is very weak, the ground temperature is not high, and strong convective air currents cannot be formed, and of course, hail cannot be formed.

Hail and rain, copy

Snow all fell from the clouds.

Hail plague will du

In the summer, meteorology is called precipitation.

zhi refers to the natural phenomenon of water falling from the atmosphere to the earth's surface, and it includes rain, snow, hail, and so on.

Clouds are formed by water vapor. In the high altitude, due to the low temperature, the particles suspended in the air absorb the water in the cloud and form very small water droplets or ice crystals, which continue to absorb the water in the cloud and gradually form larger water droplets (Xiaoice crystals can also become larger water droplets when absorbing a large amount of water). As they absorb the water from the clouds, the droplets grow until their weight exceeds the levitating force that the air can provide, and then they fall to the ground to form rain.

If the temperature is very low, the water precipitated in the cloud is frozen into Xiaoice crystals (the extremely small water droplets that have formed in the cloud can also be frozen into Xiaoice crystals), and the Xiaoice crystals absorb water and continue to expand, forming hexagonal larger ice crystals, and when the hexagonal crystals are large enough to exceed the buoyancy of the air, they fall into snow.

Hail is the size of ice particles and ice that fall from the sky, and its particle size is generally 5-10 mm, and the largest particle size recorded in the literature can reach more than 300 mm. Hail from the sky can cause great damage to houses, people, livestock, crops, etc., and form a disaster. Hail is a product of convective weather, formed in thick and strong cumulonimbus clouds, and meteorologically said to be deep stratification without concealment.

Relatively large ice particles can be produced in the development of thick cumulonimbus clouds. However, it does not necessarily fall to the ground and become hailstones, only when those ice particles rise and fall repeatedly in the high-altitude clouds with the air current, and continue to grow to a large enough particle, they will fall from the sky into hail.

First of all, let's explain why it rains, because the sun evaporates the moisture from the ground into water vapor and starts to rise.

Entering the clouds, so that the superimposed clouds can not bear the weight of water vapor [At this time, the temperature at high altitude is enough to make the water vapor into small water droplets, and the water droplets begin to fall downward, of course, snow and hail are because the temperature at high altitude solidifies the water droplets, and the rain, snow and hail formed in a certain temperature segment [personal answer].

Water evaporates into the air to form water vapor, and when it is cold in the air, it gathers into large water droplets, and when it falls, it becomes rain, and these large water droplets turn into snow or hail when they encounter very cold air.

It's going to rain, and my mother wants to remarry, so let it go.

In fact, snow and hail work on the same principle. Only the temperature difference can determine whether it will snow or hail。In short, hail requires a large temperature difference to cause strong convection, i.e., relatively high temperatures near the surface, very strong updrafts, and strong updraft activity.

Only when the weather is cold can the Xiaoice crystals be lifted, grow in the air, and eventually fall like hailstones. In winter, the air surface temperature is low and there is no strong convection, so when the weather is cold, the air will condense into water droplets or directly into snow

In spring and summer, due to the influence of the warm and humid airflow from the south, the air is humid, and at the same time, the solar radiation is strong, the air near the ground is constantly heating up, and the upper cold air is sinking, which is easy to form strong convection, so there are many thunderstorms and even hail。Snow, like rain, is the condensation of cloud droplets. When the temperature in the cloud is above 0 degrees, there are no ice crystals in the cloud, only small water droplets, and then it will only rain.

If the air temperature in and below the clouds drops below 0 degrees, small water droplets will condense into ice crystals and snowflakes that will fall to the ground. In winter, the temperature is low, so it snows.

First it rained, then it rained. When moist air and cold air at high altitude are convection, the cold air condenses the moisture in the moist air, then collides with each other and increases, and finally the rising hot air cannot lift the water droplets, and eventually becomes a rainfall phenomenon。When the temperature difference between low and high altitudes is particularly large, when the lift of the hot air is greater than the gravity of the falling water droplets, the rain will not fall.

This is similar to flying a kite in the spring. The rising air flow lifts the water droplets high. When the air reaches a high-altitude and low-temperature environment, small water droplets condense, aggregate into large water droplets, and then freeze into ice particles.

When the rising air flow can't rise, the hail falls!

The cold spell of winter causes snowfall。The cold wave itself is an intense, dry, and cold air that flows from north to south. When its leading edge comes into contact with the warm, moist air from the south, it lifts the warm, moist air to the air because it is heavier than the warm air, causing the water vapor in the warm air to quickly condense into ice crystals and gradually form snowflakes.

When it's cold, the atmosphere is cold, so the rain turns into snow.

This is due to the different weather temperatures, which condense into different densities of moisture in the clouds.

I think it's because when it's cold, snow doesn't form hail.

That's the magic of nature, and I think it's amazing.

Hail must form in convective clouds, and when the water vapor in the air rises with the air current, the higher the height and the lower the temperature, the water vapor will condense into liquid water droplets; If the altitude continues to increase and the temperature drops below zero degrees Celsius, the water droplets will condense into solid ice particles.

Snow is solid precipitation in the shape of a star, hexagonal shape, or column of six branches composed of ice crystals. Due to the low temperature, water vapor is directly condensed in the air. Sometimes there are needle-like crystals, and when it is not very cold, many snowflakes fuse into clumps (like cotton wool).

The snow falling from Nimbostratus (or Altostratus or even Cirrostratus) is continuous, and there is no sharp change in snowfall intensity. When snow falls, the sky is mostly evenly covered with clouds. Snowfall generally occurs in the cold and temperate winters, so the formation of snow requires lower temperatures, and you can't form snowfall in the lower latitudes and higher winter temperatures.

Water on the ground (seawater, river water, lake water, river water, etc.) is evaporated into water vapor and rises into the air by sunlight, because the temperature at high altitude is much lower than that on the ground, sometimes even below freezing. In a low-temperature environment, water vapor condenses into small water droplets. The clouds in the sky are formed by the aggregation of these small water droplets.

The clouds are located in very low temperatures, so the bigger the ice balls will be, and the more they will melt into rain. Therefore, there is a lot of hail in the summer. In winter, snow and ice fall due to the low ground temperature, so it will only snow in winter.

The water on the ground (seawater, river water, lake water, river water, etc.) is evaporated into water vapor by sunlight and rises to the air and rises, because the temperature at high altitude is much lower than that of the ground, sometimes even below freezing. In a low-temperature environment, water vapor condenses into small water droplets. The clouds in the sky are formed by the aggregation of these small water droplets.

These small water droplets in the clouds collide with each other by the movement of the air, making themselves larger and larger. The water droplets that gradually become larger and freeze due to the action of low temperature to form Xiaoice beads (actually snow), the Xiaoice beads collide with each other or their appearance continuously condenses the water vapor in the air, so that their volume continues to increase, and the oversized ice beads fall to the ground because they are too heavy, so that the updraft can not be supported, and the ice beads heat up due to air friction in the fall and the high temperature of the ground in summer gradually melts into water droplets-raindrops; If the ice droplets are too large (actually called "ice hockey balls") before they fall to the ground, the smaller ones that fall to the ground can melt before they melt and become rain, and the slightly larger ones can only be hail and shiver. The air currents in the cotton-soft clouds floating in the air are always in a state of intense motion, which causes the clouds to move up and down, forming thick clouds like white mushrooms (a type of cloud that is common in summer).

Because the clouds are located in extremely low temperatures, the larger the ice balls form, the more they fall to the ground, the more they melt into rain. Therefore, there is a lot of hail in the summer.

In winter, the snow and ice that fall due to the low ground temperature cannot melt into rain in the middle of the winter, so it will only snow in winter.