The cause of the heavy rain

The reasons for this heavy rain are as follows:

1. From the macroscopic physical conditions, sufficient and continuous water vapor, strong and persistent updraft and unstable atmospheric structure are the main physical conditions for this rainstorm. The favorable combination of various scales of weather system and underlying surface, especially topography, can produce heavy rain. The main weather systems that cause large-scale rainstorm in China are fronts, cyclones, shear lines, eddies, troughs, typhoons, easterly waves and intertropical convergence zone.

2. Topography also affects the formation of rainstorm and rainfall. For example, due to the existence of mountains, the airflow is forced to rise on the windward slope, which increases the vertical movement and the rainstorm; On the leeward slope of the mountain range, the airflow sinks and the rainfall is greatly reduced. On some leeward slopes, the rainfall is only110 of windward slopes.

In early August, at 1963, there was a wet air flow from the South China Sea to North China, which happened to intersect with Taihang Mountain. Due to the uplift of the mountain range, there is a rare rainstorm in the east of Taihang Mountain. The narrow tube action of the valley can also strengthen the rainstorm.

Rainstorm (English name Churchill rain；; ; Heavy rain; Storm) refers to rain with high precipitation intensity, which is often formed in cumulonimbus clouds. According to China's meteorological regulations, heavy rainfall with 24-hour precipitation exceeding 50 mm is called "rainstorm". According to its precipitation intensity, it is divided into three grades, namely, 24-hour precipitation of 50-99.9 mm is called "rainstorm", 100-249.9 mm is called "heavy rainstorm", and more than 250 mm is called "extraordinary rainstorm".

Harmful effects:

Rainstorm is one of the main meteorological disasters in China. Long-term rainstorm is easy to produce water accumulation or runoff flooding low-lying areas, resulting in floods. According to the statistics of 1950 ~ 1999, the average flood disaster area in China for many years is 9.424 million hectares, and the affected area of farmland in severe flood years can reach more than130,000 hectares.

Rainstorm is a kind of disastrous weather with serious influence. Continuous rainstorm, heavy rainstorm and extremely heavy rainstorm in a certain area will often lead to flash floods, reservoir dam breaks, rivers flooding, houses being washed away, farmland being flooded, traffic and telecommunications being interrupted, which will bring serious harm to the national economy and people's lives and property. Heavy rain, especially large-scale continuous heavy rain and concentrated heavy rain, not only affects industrial and agricultural production, but also may endanger people's lives and cause serious economic losses.