After Shanghai, Jiangsu is experiencing hail! What kind of weather phenomenon is this hail that looks like both fertilizer and sugar?

Edit: Corner

On February 22, according to the Nanjing Meteorological Bureau, as Nanjing is near the frost line, the rain and snow phase changes are complex, and the main weather in the city is "sleet". On the same day, Wuxi, Zhangjiagang, Suzhou, and Changshu also had small ice beads that were distinct and spherical, looking like fertilizer, sugar, and hail at first glance. So what is this "sleet"? Is it a new weather phenomenon?

Actually, it is not. According to Guangming Online, Shanghai also had hail on February 5, but it was not a large amount of hail and was nicknamed "scalp snow" by citizens.

This kind of "snow" that looks like fertilizer is called graupel (xiàn) in scientific name. It is a kind of solid precipitation, also known as snow pellets or soft hail. The graupel this time is due to the special form of precipitation caused by temperature stratification. The formation of graupel is usually caused by snow crystals contacting supercooled cloud droplets (liquid supercooled water droplets with a diameter of less than 10 microns), snow crystals providing condensation nuclei, and supercooled cloud droplets quickly condensing on the surface of snow crystals. According to the "China Weather" Weibo, there are three ways to distinguish whether the snow in front of you is snow. Snow, graupel and ice pellets are all solid precipitation, but there seems to be little difference to the naked eye, so many netizens will confuse the three. In fact, they can be distinguished by shape, size and sound.

1. Look at the shape: Snow is mostly hexagonal in shape, with many varieties, and falls from the sky one piece at a time, hence the name "snowflakes"; sleet is composed of ice particles, which are white and opaque, and spherical or nearly spherical cones in shape; ice particles are transparent and spherical or irregular in shape.

2. Look at the size: Snow is small and not easy to break when it hits the ground; the diameter of sleet is usually 2 to 5 mm and it is easy to break when it hits the ground; the diameter of ice particles is usually less than 5 mm and they are hard and not easy to break.

3. Listen to the sound: Snow falls to the ground relatively quietly, so it is often described as "snow falling silently"; hail falls to the ground and bounces with a sound, but the sound is weaker; ice particles fall to the ground and bounce with a crisp sound.

How cold is it when it rains hail? Emperor Wen of Sui's daughter was frozen to death

There were records of "hail" in ancient China very early. In the oracle bone inscriptions, there were already records of various weather conditions, among which the word "hail" appeared.

"The Book of Songs·Xiaoya·Lubian" once wrote: "Like rain and snow, the first thing that gathers is sleet." It represents people's understanding of sleet in the pre-Qin period.

Song Dynasty poet Yang Wanli once wrote a poem called "Hail", which mentioned "Snowflakes send hail as the vanguard, breaking through the panic and darkening the sky." It accurately describes the fact that hail falls before heavy snow. Compared with snow, hail is easier to hear, so many poets write this auditory feeling into poems.

Cai Xiang of the Song Dynasty mentioned in his poem "Returning Home in March" that "I heard the falling snow while sleeping on the river, and picked new seedlings for wild rice." Zhang Lei, also from the Song Dynasty, also wrote "Spring snow on the south mountain, frozen clouds, dark fire and green lamp, rapid sound of snow."

Snowfall also means extreme cold. Yang Lihua, the eldest daughter of Emperor Wen of Sui, and the empress and empress dowager of the Northern Zhou Dynasty, was probably frozen to death in snowfall. The Book of Sui records that Emperor Yang of Sui went on a western tour "on the eighth day of the sixth month, Guimao, through the Dadouba Valley, where the mountain roads were narrow and dangerous, and the soldiers came out in a line. The wind and snow were so dark that the soldiers lost contact with the officials, and more than half of the soldiers froze to death." Yang Guang's team encountered strong winds and snowfall. Half of the guards in Yang Guang's team froze to death. It is very likely that Yang Lihua was frostbitten and infected during this weather change, and finally died in the Hexi region.

At present, in response to this sudden extreme weather, the Wuxi Meteorological Observatory upgraded and issued an orange warning signal for road icing at 16:00 on February 22: Due to rain, snow and low temperatures, it is expected that from the night of February 22 to the morning of February 23, most streets and towns in Wuxi will experience road icing that will have a serious impact on traffic.

According to many citizens and group members, the road in Xicheng was very slippery from February 22 to February 23, and many traffic accidents occurred. Therefore, in addition to cars, electric vehicles, bicycles, and pedestrians, everyone should drive slowly on the road. Once again, we remind everyone in the Jiangsu, Zhejiang, and Shanghai regions that when traveling during these two days, everyone must take anti-slip measures to avoid danger.

Reference sources: Guangming.com, The Paper, Wuxi News, Jiangsu Meteorological Bureau, Suzhou Evening News