The side effects of drying out -

When water evaporates, sometimes things get left behind. There's a fancy term for that, called "efflorescence" - the salts get deposited on your masonry.
 On walls, it looks like a white stain. In my basement, it looks like a science fair project.

Not snow. Or frost.

Must be aliens.

Salt aliens.

It's hard to tell, but that fluffy white stuff is a crystalline structure "growing" out of my floor. Dehumidifier is doing it's job! This weekend I should vacuum the basement again.