Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download Hand Painted Winter Pack Free.
Hand Painted Winter Pack v1.0
Update 1.1: Removed missing scripts warnings in the demo-scene
Stylized assets to create your own fantasy winter or ruins environment!
Video walkthrough 2
Compatible with unity terrain tools.
Includes an example scene to get you started:
_Models range from 40 to 2200 triangles.
_Trees, plants, grass, flowers models.
_Ruins, statues, walls, fences, flags, gate models.
_Rocks, cliffs, iceberg, mountain models.
_Particle effects, Snow fall and blizzard