The hair is amazing. ...I'm not certain it wouldn't be a good idea to have a bit darker outline on the background objects? She stands out to such a degree that to me the falling debris looks rather flat by comparison. But this may just be a stylistic preference!
I see you requested a critique. I think her right leg might be a bit long. One trick that helps me is to hold up the sketch in a mirror or flip the canvas digitally. This helps me check proportions and such.
Nice job. I like the textures and colors. Keep it up!
The way you did her hair is great, the lighting brings out the beautiful flow of it. The way the coat flows is off though, the air rushing up would cause it to balloon up and raise straight up, not to the back- though this is an idealized version of the scene, so it makes sense why it isn't. Her face came out well, it has a lot of personality in it. The piece doesn't quite give off the falling feel though, but I'm not sure how to fix that. Great piece!