The Central Meteorological Observatory upgraded and issued an orange rainstorm warning. How is the grade of rainstorm divided?

The Central Meteorological Observatory upgraded and issued an orange rainstorm warning, and the rainstorm level was divided according to the rainfall. There are frequent rainstorms in some parts of our country, especially in the summer rainy season, and the harm of rainstorms is also great. The previous rainstorm in Henan brought some losses to many Henan people. Once the rainstorm continues, it will lead to floods and soil erosion, which will seriously lead to major economic losses such as dike burst, flooding of crops and collective flooding of vehicles. In mountainous areas, geological disasters such as mountain torrents, landslides and mudslides will also be triggered, which will threaten the safety of people's lives and property in serious cases. Therefore, the rainstorm warning of the Central Meteorological Observatory is very important. Rainstorm warning can inform people in advance to make relevant preparations, so as to better cope with various disasters caused by rainstorms. The level of rainstorm warning is generally divided into four levels, which are represented by blue, yellow, orange and red respectively. These grades of rainstorm are classified according to the unit of rainfall, that is to say, there is no evaporation and infiltration after the rainfall falls on the ground, and then the depth of rainwater accumulation is measured to determine, and the unit is millimeters. The blue rainstorm warning is the smallest rainstorm warning, which means that the rainfall is more than 50 mm within 12 hours. Then there is the yellow rainstorm warning, that is, the rainfall in six hours is more than 50 mm. The orange rainstorm warning means that the precipitation exceeds 50 mm within three hours. The red rainstorm warning is the highest level warning and the most serious. That is, the precipitation reaches 100 mm or more within three hours. At this time, everyone should be nervous and get ready. Therefore, everyone must pay more attention to the weather forecast and the warning level of heavy rain, so as to better plan ahead and take preventive measures in time. If the house is low-lying, it is necessary to place some water retaining objects and pumping devices such as pumps. Drive less and wait patiently at home. In case of rainstorm, high voltage electricity, telephone poles, etc. Should be used to prevent electric shock. If the car stalls in the water, be sure to get off and wait for rescue at a height. Don't stay in the car