Rainstorm refers to the number of millimeters of rainfall in 24 hours.

Heavy rain generally refers to the rain with a daily (24-hour) precipitation of 25-49.9 mm or the rain with a daily precipitation of 8. 1- 16.0 mm 1 hour.

According to the traditional synoptic definition, precipitation is defined as light rain (0 1~9.9mm/d) and moderate rain (10~24. 9mm/d), heavy rain (25~49.9mm/d), heavy rain (50.0 ~ 9.9m m/d) and torrential rain.

In the process of rain formation, large water droplets play an important role. When the radius of water droplets increases to 2-3 mm, it is difficult to maintain such a large water droplet by the attraction between water molecules. In the process of falling, it is easy to be split by the impact of airflow, and large water droplets will fall through a "chain reaction".

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Rainstorm prevention measures:

1, try not to travel in the rain. At this time, the umbrella may have no effect. The wind will roll the rain into the umbrella from all directions, so you should avoid it in time.

Don't ride a bike when it rains heavily, and pay attention to the water depth when crossing the road.

3. If you really need to travel in the rain, try to choose a raincoat in terms of rain gear. When wearing a raincoat, pay attention to the visibility of the hood and eyes.

4. Heavy rain will turn into rainstorm at any time. At this time, we should pay attention to prevent geological disasters such as mountain torrents and mudslides, and do not take shelter from the rain in low-lying places.

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