What kind of rain can be called a rainstorm?

A weather phenomenon that produces heavy rainfall in a short period of time.

Specifically, the rainfall within 24 hours is greater than or equal to 50 mm, while the definition of rainstorm in meteorology is more stringent.

According to the national meteorological standard "Precipitation Grade" issued by relevant departments, there are two different regulations on rainfall according to the cumulative rainfall time. At the same time, it can be divided into two levels: rainstorm and heavy rainstorm. From this standard, we can see that:

Not all rainstorms are fierce. Even the rain in Mao Mao may form a rainstorm if it lasts long enough.

Rainstorm refers to:

12 hour rainfall reaches 30~69.9 mm, and 24 hour rainfall reaches 50~99.9 mm;

And the rainstorm refers to:

12 hour rainfall is 70 ~139.9mm, and 24 hour rainfall100 ~ 249.9mm;

As for the rainstorm:

Yes 12 hour, with rainfall above 140 mm and 24-hour rainfall above 250 mm.

In the specific case of China:

Because there is little annual rainfall in the inland areas of northwest China, the probability that the daily rainfall can reach more than 50 mm is even rarer. According to this standard, it is difficult for the northwest region to reach the magnitude of rainstorm. But the reality is that short-term heavy rainfall in northwest China will also lead to various natural disasters.

Therefore, in some areas of China, the criteria for judging rainstorm will be re-divided according to the actual situation in the area, such as daily rainfall greater than or equal to 25mm or 30 mm.

According to the rainfall range, rainstorm can be divided into local rainstorm, regional rainstorm and heavy rainstorm.

Among them, the duration of local rainstorm is usually several hours to dozens of hours, and the impact range is tens to thousands of square kilometers, which causes less harm, but it may also have a greater impact on the region when the rainfall intensity is particularly large.

The regional rainstorm usually lasts for 3~7 days, and the influence range is10 ~ 200,000 square kilometers. When the rainfall intensity is particularly large, it is easy to cause regional torrential rains and floods.