2
$\begingroup$

What is the reason that before a heavy shower of rain, a few droplets always seem to fall? Why doesn't the heavy shower begin at once?

While freezing water, for example, some parts of the water such as the surface freeze the first, but in the example of rain, the condensation process seems to happen much faster. I am trying to understand how this process starts so slowly yet becomes so fast in a matter of seconds.

The reason for this might appear to be due to the "size" of the droplets and drag. However, the droplets that fall before appear approximately the same size as those in the downpour, also the time difference between the raindrops is too long.

$\endgroup$
1
$\begingroup$

The lighter the particle, the greater the effect of atmospheric drag. Tiny particles can remain suspended for a very long period of time, but larger particles drop out of suspension more quickly. The same is true for raindrops. The smallest raindrops have a lower terminal velocity and take longer to reach the ground.

When the rain-producing region moves over your location, there will be a distribution of sizes for the raindrops. Out of that distribution, the largest raindrops will fall the fastest and will win the race to reach the ground first.

$\endgroup$
1
  • $\begingroup$ Wouldn't the time difference between them be much smaller? Also, the rain droplets falling before the downpour appear smaller or much like regular droplets $\endgroup$ – ten1o Mar 16 at 12:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.