Usually ballet dancers always have their hair tied up in a severe bun and you can't tell how long it is or even tell the girls apart on stage, they look so similar.
I guess it keeps hair from getting caught on anything and from hitting the male in the face when they twirl.
This photographer really let people see a look from this dancer no one has ever seen. (It's almost looks like Ribbon Gymnastics)
A Long Hair Pic is also on the Dance Company Website: