gorgeous emotion and posing in this piece!
The way you have the head and neck bent and the back arched are perfect!
If I could offer some constructive critique to this piece, I would say that I think the front legs, where the ankle meets the paw, is a little bit stiff. It seems that that is too flat or straight of a line and then it just abruptly goes up into the arm, much the way someone's heel just goes into their leg. This isn't the effect you want... and it makes the paw seem too big. You want to arch the ankle up more, so that it seems more natural and graceful.
Also, the back feet are a bit too small, proportionately. But only a little bit.
Overall the posing is ABSOLUTELY GORGEOUS. I really really love it.
The way you did the snowflakes is wonderful, and I love the color of the sky. It's very fitting. I think for the background the only thing you would need to work on is the interaction between the character and the snow. Right now she is just sitting on it as if it were a flat stiff surface, when normally her paws and tail would be somewhat under the snow, and causing it to sort of form around her where she is sitting... if you know what I mean. Kind of hard to put in words per se...
Overall I ADORE this piece so keep up the fabulous work!!!!