Why is the weather in Beijing always bad this year? It still snows in spring? !

as we all know, clouds are made up of many small water droplets and small ice crystals, and raindrops and snowflakes are made up of these small water droplets and small ice crystals. So, how is snow formed?

in water clouds, all the cloud droplets are small water droplets. They mainly grow into raindrops by continuing to condense and collide with each other.

ice cloud is made up of tiny ice crystals. When these small ice crystals collide with each other, the surface of the ice crystals will heat up and melt, and they will stick to each other and freeze again. Repeat this for many times, and the ice crystals will increase. In addition, there is water vapor in the cloud, so ice crystals can continue to grow by condensation. However, ice cloud is generally high and not thick, where there is not much water vapor, the growth of condensation is slow, and there are not many opportunities to collide with each other, so it cannot grow to a great extent to form precipitation. Even if it causes precipitation, it is often evaporated on the way down and rarely falls to the ground.

the mixed cloud is the most favorable for the growth of cloud droplets. The mixed cloud is composed of small ice crystals and supercooled water droplets. When a mass of air is saturated for ice crystals, it is not saturated for water droplets. At this time, the water vapor in the cloud condenses on the surface of the ice crystals, but the supercooled water droplets are evaporating, which produces the phenomenon that the ice crystals "adsorb" the water vapor from the supercooled water droplets. In this case, ice crystals grow rapidly. In addition, supercooled water is very unstable. If you touch it, it will freeze. Therefore, in mixed clouds, when supercooled water droplets collide with ice crystals, they will freeze and adhere to the surface of ice crystals, making them grow rapidly. When small ice crystals grow to overcome the resistance and buoyancy of air, they fall to the ground, which is snow.

In early spring and late autumn, the air near the ground is above ℃, but this layer of air is not thick and the temperature is not very high, which will make the snow fall to the ground before it can completely melt. This is called "wet snow", or "both rain and snow". This phenomenon is called "sleet" in meteorology

Similarly, the size of snow is classified according to precipitation. Snow can be divided into three types: light snow, medium snow and heavy snow

So snow has nothing to do with seasons. As long as there is a cold wave and the weather is cold enough, snow will form.

There are not only Chun Xue now, but also poems in the past.

Chun Xue

Han Yu

There are no flowers in the New Year.

In early February, I was surprised to see grass buds.

Snow is too late for spring, so

it wears a courtyard tree as a flying flower.