Knowledge post! Why is the ＂blizzard＂ mentioned in the weather forecast, and the snowfall is only a dozen millimeters？

　　CCTV News:The Central Meteorological Observatory continued to release on the 3rd.Blizzard yellow warningAffected by the eastward movement of the south branch trough and the southward cold air, there will be a large-scale rain and snow weather process in most parts of central and eastern China today and tomorrow, with moderate to heavy snow in the eastern part of northwest China, southwestern part of North China, most of Huanghuai, Jianghan and Jianghuai. Among them, there are blizzards in parts of central and southern Shaanxi, western and northern Hubei, southern Henan and northern Jiangsu and Anhui (10~ 18 mm), local snowstorm.

　　Seeing the weather forecast, many netizens were puzzled: didn’t they say "Blizzard"? Why is it only a few tens of millimeters? It’s not as thick as the sole. You must be mistaken! It should be in centimeters!

　　Is it true that the meteorological department made a mistake in measurement? Of course not! In fact, it is like this:Snowfall and snow depth are two different concepts. Snowfall does not refer to the snow depth, but the precipitation value in winter.

　　How is the snowfall level divided?

　　The snowfall level is not divided according to the thickness of snow on the ground. According to the standards of the meteorological department, due to the size, shape and density of snow falling on the ground, the snowfall isAccording to the amount of water after the snow melts, divided into multiple levels from low to high.. The snowfall levels are as follows:

　　Light snow: the snowfall within 12 hours is less than 1.0 mm (equivalent to the amount of melted rain, the same below).

　　Medium snow: the snowfall is 1.0 ~ 3.0mm in 12 hours or 2.5 ~ 5.0mm in 24 hours.

　　Heavy snow: snowfall is 3.0 ~ 6.0mm in 12 hours or 5.0 ~ 10.0mm in 24 hours.

　　Blizzard: The snowfall is more than 6.0 mm in 12 hours or more than 10.0 mm in 24 hours.

　　In many places, sometimes the snowfall will be much greater than 10 mm, so many places and forecasts also introduce the concepts of heavy blizzard and heavy blizzard with reference to the two levels of heavy rainstorm and heavy rainstorm.

　　Blizzard: A snowfall process in which the snowfall is 20.0 ~ 30.0 mm within 24 hours.

　　Heavy snowstorm: the process of snowfall with a snowfall of more than 30 mm within 24 hours.

　　In addition, in life, we occasionally see snow falling, but it can’t form snow. This kind of snowfall is called "sporadic light snow".

　　Now, I finally know why the snowfall of more than ten millimeters can be called blizzard ~

　　▌Source of this article: CCTV News Synthesis, China Weather Network, China News Network.