Why and how does nose bleed?

Nose bleeds are caused because tiny little blood vessels that are in the septum( which is the thin area between the nostrils) break for various reasons. If your nasal passages get too dry, your nose may bleed. If you pick your nose, chances are, your nose will bleed. Taking cold medicines too often can bloody your nose as can getting socked in the nose or bumping it on something. High elevation can be the reason for a nose bleed too.

Regardless of why your nose began to bleed, what is happening is that the tiny blood vessels are bursting and releasing blood. When it bleeds out, it is nature's way of keeping the blood from going back into your system so it's all good, just inconvenient.