What are the definitions of freezing rain, frost and hail? What is the weather symbol? What's the harm?

1. Freezing rain is a kind of disastrous weather in early winter or late winter and early spring, which is composed of ice-water mixture and freezes immediately after colliding with objects with a temperature lower than 0℃.

Raindrops below 0℃ can remain supercooled in air with a temperature slightly lower than 0℃, and their appearance is the same as that of ordinary raindrops. When they fall on an object with a temperature below 0℃, they will immediately freeze into a smooth and transparent ice layer, which is called snowball. Severe snowstorms will crush trees and telephone poles, stop communication and power supply, hinder road and railway traffic, and threaten the flight safety of aircraft.

2. Frost is a common agrometeorological disaster, which means that the temperature drops suddenly, and the surface temperature drops below 0℃, causing damage to crops and even death.

When the temperature drops below 0℃, the water in the intercellular space forms ice crystals, and the protoplasm and vacuoles in the cells gradually dehydrate and solidify, leading to cell death. During thawing, the ice in the intercellular space melts into water and evaporates rapidly, and the protoplasm dries up the plants due to water loss.

The water on the local surface is evaporated by sunlight and then rises into the air. A lot of water vapor condenses into clouds. The relative humidity at this time is 100%. When it meets cold air, it will liquefy, and the dust in the air will form raindrops (tropical rain) or ice crystals (mid-latitude rain), and it will become bigger and bigger. When the temperature drops to a certain extent, the water vapor in the air will be supersaturated, so it will rain.

If you encounter cold air without condensation nuclei, water vapor will condense into ice or snow, which is snow. If the temperature drops sharply, it will form a bigger ice mass, which is hail.

Extended data:

Freezing rain mostly occurs in winter and early spring. In China, Guizhou is the region with more freezing rain, followed by Hunan, Jiangxi, Hubei, Henan, Anhui, Jiangsu, Shandong, Hebei, Shaanxi, Gansu and southern Liaoning. Among them, there are more mountains than plains, and the mountains are the most. When freezing rain accumulates to a certain extent, it is not only harmful, but also very harmful.

If the temperature drops to MINUS 3℃, there will be severe frost, and besides a lot of fallen leaves, the ear neck will freeze to death. This not only seriously affects the photosynthesis of maize plants, but also cuts off the channel of transporting nutrients from stems to grains, and the filling is forced to stop, which often leads to a sharp decline in yield. When the first frost appears, if the crops are ripe and harvested, no matter how serious it is, it will not cause losses.

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