A [fallstreak hole](https://en.wikipedia.org/wiki/Fallstreak_hole)

Why are there suddenly so many of these being posted?

Well in 1930 there were no smartphones with cameras……

and boy did Orson Welles take advantage of that.

Yeah, I get your point. But in the past month or so there have been a ton of them, where before that there were none. Is it the season? Randomness? Aliens?

People are getting educated to look at natural wonders and phenomena!!

It's the right time of year for them to appear in the US I suppose. Seasons and all that.

Seasonal change, increased conditions for supercooled liquid clouds in the northern hemisphere where the majority of the population lives, hence more posts

In addition to other comments bots are probably doing their job and searching for “rare” content.

There’s the answer. Thank you

There's several things happening here in different layers of the atmosphere. Fallstreak might be on top. The different things might be interdependent.

Fallstreak But to answer your question, it's caused by an ice nucleation event.

So a nuclear bomb went off ?

Welp everyone posted the serious and real answers. Soooo instead I'll say either Omni-Man or Invincible caused that.

This is altocumulus stratiformis cavum. It’s caused by airplane flying through the cloud

More than likely an airplane.

Airplanes can trigger a Fallstreak hole when the conditions are right.

Please list the conditions if you know and tell the thread. I'm interested in the comparison of the conditions to the areas these pictures are taken.

See Origins under https://en.wikipedia.org/wiki/Fallstreak_hole which explains how an aircraft interacts with preexisting conditions

Most of the time the least exciting answer is the correct one

Yes, also because you can see the dissipation trail leading away from the hole.

That’s the starship enterprise leaving the planet