What is the phenomenon of sudden black clouds in the sky at night? It was completely dark and there

Completely black is a prelude to a rainstorm and is usually no other color.

Regional rainstorms can generally last for 3 7 days and can affect an area of up to 10.2 million square kilometres.

or greater, the damage is average, but sometimes due to the intensity of rainfall.

It is extremely strong and may cause severe rainstorm and flood disasters in the region.

Extraordinarily large rainstorms last the longest, generally a combination of consecutive rainstorms in multiple areas, and the rainfall can last intermittently for about 1 3 months, and the rain belt lasts for a long time.

Heavy rainfall is a disastrous weather that often causes flooding and severe soil erosion, resulting in major economic losses such as engineering failures, embankment failures and crop flooding. Especially for some low-lying and closed areas, rainwater cannot be quickly discharged, resulting in water accumulation in farmland and oversaturation of soil moisture, which will cause more disasters.

Harmful effects

Heavy rain is a major meteorological disaster in China.

One. Prolonged heavy rainfall is prone to water accumulation or runoff to inundate low-lying areas, resulting in flooding. According to the statistics of 1950 and 1999, the average annual flood area in China is 10,000 hectares, and the area of farmland affected in severe flood years can reach more than 13 million hectares.

Heavy rain is a severe form of severe weather.

Heavy rains or heavy rains or extremely heavy rains in a certain area often lead to flash floods, dam collapses, rivers overflow, houses are washed away, farmland is inundated, and transportation and telecommunications are interrupted, which will have a negative impact on the national economy.

and people's lives and property. Heavy rains, especially large-scale and persistent rainstorms and concentrated heavy rains, not only affect industrial and agricultural production, but may also endanger people's lives and cause serious economic losses.

What is the phenomenon of sudden dark clouds in the sky during the day? The sky is still dark green at times.

A: It's going to rain heavily.

What is the phenomenon of sudden black clouds in the sky at night? It's completely dark.

A: If it rains next, it is.

Rainstorm. If it doesn't rain next, it will be the collapse of the Cumulonimbus tower elsewhere, and the dark cloud will "flow" on your head, and if the collapse is on your head, it will be called a storm.

Don't think it's miasma.

Why is the sky dark at night Read The answer is: Although the universe is infinite, there is a limit to the number of celestial bodies where light can reach us. As long as those finite celestial bodies reach our Earth with less light than the Sun, the day and night on Earth depend on the Sun.

If only the universe hadn't expanded. There is no problem of night darkness when you tremble. It follows that night darkness is the result of the expansion of the universe.

Astronomers Hubble and others have found that almost all extragalactic galaxies are moving away from us, that is, the universe is expanding like an inflated balloon, getting bigger and bigger; The farther away galaxies are from us, the faster we move away (i.e., the speed of regression). The receding galaxies weaken the light radiated to us by galaxies; Extragalactic galaxies, which are far away from us and starved far away, may recede at the speed of light, so that the light emitted cannot reach us.

Dark means that after the sun has set, the sky turns dark. Not well lit, not bright. Due to the rotation of the earth, the day and night are black and white.

The sky is dark and Hui Hui returns to the scene of the earth when it rotates against the sun, which is mostly used to describe the sky at night, the general sunset time is about 18 o'clock, after sunset to the next day before sunrise is the dark period, and the clear night is often accompanied by the moon and stars. When the sun sets, there is no sunlight shining on the sky, and it is dark, which is called dark.

In astronomy, the standard of darkness and dawn is defined as the sun's position 12°30' below the horizon, that is, some time after sunset. During this time, the length varies with different latitudes, and the same coordinate location is theoretically different every day, because the angle between the sun and the earth changes every day, but there is little difference throughout the year. Taking Tiananmen Square in Beijing as an example, on the winter solstice, the dark hour is 28 minutes after the sunset time, and on the summer solstice, the dark hour is 30 minutes after the sunset hour, a difference of only two minutes.

1. The thickness of the cloud layer is different, the cloud layer is very thick, and the light of the sun and the moon is difficult to transmit through, and the cloud body looks very black, on the contrary, the cloud layer is relatively thin, and the cloud will appear gray and white. 2. Isolated cumulative clouds, because the clouds are relatively thick, the sunny side, the light is almost all reflected, so it appears to be white; On the backlit side and its bottom, the light is not easy to transmit, and it looks grayish and black. Difference Between White Cloud and Black Cloud:

1. The thickness of the cloud layer is different, and the black cloud layer is generally thicker, and the white cloud layer is relatively thin. 2. The density of fog droplets is different, and the density of black cloud droplets is generally denser, and the density of white cloud droplets is worse.

Extended information: The reason why there are various colors in the sky: at sunrise and sunset, the light is obliquely reflected, and the water vapor and impurities in the air make the short waves scatter a lot, and the long wave parts of red and orange are retained, so they appear red, orange and other colors.

When ice crystals are present in clouds, light rays are also diffracted like prism spectroscopy. This creates a colored aura.

1. The sky is full of dark clouds, black pressure, thunder rolling, after a while, the wind is fierce, the branches are swaying and rattling, the ground is flying sand and stones, the pedestrians are in a hurry, and after a while, the raindrops of beans are crackling and falling.

2. At noon, when the wind was beautiful and the sun was beautiful, there was a sudden wind, and it was dark for a while, lightning flashes, thunder, and heavy rain poured, and suddenly the ground became a vast ocean, and after a while, the rain stopped and the wind stopped, and a beautiful rainbow hung in the sky.

3. The sky was suddenly overcast, the surrounding environment suddenly darkened, and suddenly the rain poured down, and after a while, the water flowed into a river, and after a while, the rain stopped, and people who took shelter from the rain went to the streets.