I’m basically not doing anything interesting at all. Here’s the material:
It’s just mean free path doing all the work. Glints definitely gives a more “wet” look, you can set it to 0 to get a more powdered effect.
I’m using random megascans assets, they come with an albedo/DRT/Normal; I just wildly guessed that “T” in the “DRT” stood for transmission or something so I multiplied it against the MFP 
In direct sunlight, when the sun is at your back I feel like there’s too much light in the cavities, but well… I’m not sure. I thought maybe there was too much forward scattering so I tried adjusting the phase anisotropy but it doesn’t seem to do anything. Maybe its fine and I’ve just been staring at it for too long.
On a totally unrelated note I was expecting auto-exposure to completely destroy this (as it has a tendency to do with snow) but apparently it seems to now be calculated based off of illuminance?? or something, it works shockingly well.