Unreal Engine Snowscape

I generated the landscape in World Machine and rendered it in Unreal.
I wrote a Python script to automatically generate all the impostors for the trees.
They also use a custom Pixel Depth offset to make them work with the distance field shadows.

Unreal Engine - Snow Level

World Machine Setup

For additional details, I've built several snow heaps that I've spawned on the terrain with the grass system.

To make the snow heaps match the terrain color, I used the world position from the heaps and colored them based of the flow map from World Machine.