Why do clouds sometimes form with a straight line?

Question

A perfect example would be [this](https://www.reddit.com/r/mildlyinteresting/comments/bri0pz/the_sky_is_half_full_of_clouds_and_half_clear/?utm_source=share&utm_medium=ios_app&utm_name=ios_share_flow_optimization&utm_term=control_2) post.

In: Chemistry

Answer 1

That happens when you have air streams going up or down at that line. Usually a warm city street or a cold river is responsible.