According to the scientists today:
"Water vaporizes from the oceans and rivers forming tiny clouds. The small clouds join together and the updrafts within the larger cloud increase. The updrafts closer to the center are stronger, because they are protected from the cooling effects by the outer portion of the cloud. These updrafts cause the cloud body to grow vertically, so the cloud is stacked up. This vertical growth causes the cloud body to stretch into cooler regions of the atmosphere where drops of water and hail formulate and begin to grow larger and larger. When these drops of water and hail become too heavy for the updrafts to support them, they begin to fall from the cloud as rain, hail, etc." [From "The Atmosphere" p. 269 and "Elements of Meteorology" pp. 141-142]
- Now just for the sake of argument, let us see what the "Muslim scientists" used to formulate their understandings centuries ago based on the revelation of the Quran (revealed 1400 years ago):
Have you not seen how God makes the clouds move gently, then joins them together, then makes them into a stack, and then you see the rain come out of it...
[Noble Quran 24:43]
Meteorologists have only recently come to know these details of cloud formation, structure, and function by using advanced equipment like planes, satellites, computers, balloons, and other equipment to study wind and its direction, to measure humidity and its variations, and to determine the levels and variations of atmospheric pressure.
The preceding verse, after mentioning clouds and rain, Quran speaks about hail and lightning:
... And He sends down hail from mountains (clouds) in the sky, and He strikes with it whomever He wills, and turns it from whomever He wills. The vivid flash of its lightning nearly blinds the sight.[Noble Quran 24:43]
Meteorologists have found that these cumulonimbus clouds, that shower hail, reach a height of 25,000 to 30,000 ft. (4.7 to 5.7 miles) like mountains, as the Quran says;
...And He sends down hail from mountains (clouds) in the sky...[Noble Quran 24:43]
Now this verse may raise the question: "Why does the verse say "its lightning" while referring to hail? This seems to indicate that hail is a major factor in producing lightning. Looking to a book on the subject (Meteorology Today) we find that it says:
"Clouds become electrified as hail falls through a region in the cloud of super cooled droplets and ice crystals. As liquid droplets collide with the hail they freeze on contact and release latent heat. This keeps the surface of the hail warmer than that of the surrounding ice crystals. When the hail comes in contact with an ice crystal, an important phenomenon occurs: electrons flow from the colder object toward the warmer object. So, the hail becomes negatively charged. The same effect occurs when super cooled droplets come in contact with a piece of hail and tiny splinters of positively charged ice break off. These lighter, positively charged particles are then carried to the upper part of the cloud by updrafts. The hail, left with a negative charge, falls toward the bottom of the cloud, so the lower part of the cloud becomes negatively charged. These negative charges are then discharged to the ground as lightning. [Meteorology Today p. 437]
This information on lightning was discovered recently. Until 1,600 A.D., Aristotle's ideas on meteorology were dominant in the non-Muslim countries. For example, he said that the atmosphere contains two kinds of exhalation, moist and dry. He also said that thunder is the sound of the collision of the dry exhalation with the neighboring clouds, and lightning is the inflaming and burning of the dry exhalation with a thin and faint fire. [Works of Aristotle Translated into English pp. 369 a&b]
These are some of the ideas on meteorology that were dominant at the time of the Quran's revelation, fourteen hundred years ago.