A fox jumping into fresh snow

Create a fox jumping into fresh snow.

Fixed rules (so every model is compared on the same terms):
- Exactly one file, index.html, in the current directory. Create no other files.
- Use three.js 0.170.0 from https://cdn.jsdelivr.net/npm/three@0.170.0/ (via an import map; addons from examples/jsm are allowed). No other libraries, images, 3D models, fonts or network requests: build everything in the scene yourself in code.
- A full-window canvas that resizes with the window. No scrollbars, no text, no UI of any kind.
- The viewer doesn't steer the camera: no orbit controls, and no user input needed (the camera may move along its own path).
- The scene plays on its own as a loop of about 15 seconds with a clear beginning, middle and return to the start, and keeps looping for as long as the page is open.
- Animate with requestAnimationFrame and its timestamp so the motion speed does not depend on the frame rate.

Make it astonishing. Both scenes are shown side by side in a 30-second video on social media, where people decide in one second whether to stop scrolling:
- The very first frame is already striking: a bold composition, dramatic light and colour, motion everywhere, never a dark or empty opening.
- Each loop builds to a signature moment that makes people say "wow": the climax of the subject (the leap, the eruption, the bloom, the launch), staged like a shot in a film.
- Go beyond the obvious version of the idea: choose a surprising, cinematic take with its own mood and atmosphere, not a generic template.
- Layer it: depth and atmosphere (fog, light shafts, reflections), particles and trails, rich materials, and a slow cinematic camera move.
- It is watched at about half size on a phone: keep the main subject big and clear in silhouette.

It must work in an ordinary browser on any graphics card. You cannot open a browser to look at it, so build it carefully:
- Every frame is fully drawn at every moment of the loop: no black, blank or flickering frames or patches. Keep shader maths free of NaN and infinity (no division by a value that can reach zero, no pow() of a negative number, no normalize() of a zero-length vector), and clamp colours to a safe range before bloom or other post-processing.
- The scene fills the whole window from the first frame.
- No errors in the browser console: map "three" and "three/addons/" in the import map, and import everything you use.
- It plays smoothly on an ordinary laptop or phone (keep the pixel ratio at 2 or below).

Everything else is your choice: the look, the setting, the lighting, colour, motion and detail. Make it as breathtaking as you can. Do not ask questions; make reasonable choices.