Blizzard, a natural weather phenomenon, refers to a snowfall process in natural weather. Blizzard usually occurs from June 10 to April of the following year. In the middle and lower reaches of the Yellow River and its vicinity, the largest snowfall in the whole year is often in the "rainy" solar term in spring. The appearance of blizzard is often accompanied by strong winds, cooling and other weather, which has an impact on winter traffic and agricultural production.

Blizzard warning signals are divided into blue, yellow, orange and red; When the snowstorm weather comes, local government departments should formulate emergency plans for snowstorm warning signals to remind people to take various countermeasures.

Blizzard refers to the snowfall process of a natural weather phenomenon, which brings extreme invariance to people's life and travel; Blizzard warning signals are divided into blue, yellow, orange and red. Meteorology has strict regulations on snowfall, which is completely different from the standard of rainfall.

Snow quantity is a measure measured by meteorological observers after melting the collected snow in a certain standard container. There are strict regulations on snowfall in meteorology. Like rainfall, it refers to the amount of snowfall in a certain period of time. There are different standards for 24 hours and 12 hours. In weather forecast, it is usually to forecast the weather during the day or at night, mainly referring to 24-hour snowfall. Blizzard refers to the daily snowfall (melting into water) ≥ 10/0mm.

assay method

Snowfall observation is a routine item of meteorological observation, including snowfall, snow depth and snow pressure. The snowfall is actually the precipitation when snow melts into water. When there is snowfall, the rain receiver of the rain gauge must be replaced by a snow receiver, and the water reservoir should be taken away (the outer cylinder of the rain gauge can directly receive snowfall).

When observing, take the received solid precipitate back indoors, measure it after melting, or measure it by weighing method. When the ground around the weather station is covered by snow for more than half, the depth of snow should be observed. The observation area is generally selected in a flat and open place near the observation field, or a relatively representative flat snow surface.