meltdown

I still can't believe the snow uses a blend material for melting.

There is a certain threshold in alpha test mode which determines whether the texture shows or not, in alpha blending it is partially transparent but in alpha test it can be either fully transparent or fully opaque.
The snow is just a plain white texture with alpha mask that is a greyscale heightmap of the texture underneath.
During the animation the alpha level raises but because alpha test mode cannot show partial transparency it starts making spots that slowly expand starting on the brightest parts of the texture (which is usually the quasi "top parts" of the surface while the dark parts are the cracks and holes etc)