smoothing snow in photoshop

Camera RAW > Negative Clarity works for skin, so I don't see why it wouldn't round off some snowy corners.  You could throw in some dehaze  while you are at it

You'd need to work on a copy of the background layer so you can mask in the bits you don't want blurred

Hi

Don't overdo it and take every mark out or it will not look like snow

After white balancing your image in camera raw filter, I used a local adjustment brush in the camera raw filter with the exposure reduced and the dehaze slider set to negative

Dave