People are asking me about the light and camera setup, so I thought I'd just write about it once here...
The pic is actually two images superimposed one above the other - one being a long exposure, mainly to get the light worm, and the second being the flash shot to freeze Max in the air. Max's light with the long exposure bounced a lot of light off the snow so that's why you see good light off the snow surface and trees.
First pic is the long exposure at about 20 secs @ ISO 160 @f/5.6 on the Nikkor 16mm fisheye, no flash.
Second pic is the flash - obviously do not change the position of the camera, use a good tripod. Flashed at 1/500th sec using an Elinchrom Quadra AS head jacked up high on a stand to the left. Nikon max flash sync for a clear image is 1/250th but because Max is in the upper frame I could push it to 1/500th therefore maximizing his sharpness. Rear curtain. Camera is a Nikon D800 so plenty of resolution.
In photoshop stack the two images on top of each other using layers. If the flashed image ( mainly black except the rider ) is on top then rub out the area surrounding the rider to show through the long exposure pic beneath. Then flatten, save & post.
You can do it in one shot with the rear curtain flash at the end of a long exposure but, in my experience, you're always going to get some ghosting effect and, therefore, not the sharpest action freeze. Framing the rider against a dark background helps a lot too.
This is amazing. Wow I just saw the other version without snow and its really interesting with the snow, better contrast between whites and blacks makes this shot freaking sick! Plus you can see the stars in this one...