Mod Version:
DynamicSurroundings-1.10.2-3.4.7.2

Forge Version:
1.10.2 - 12.18.3.2511

Description:
When using the mod "Fancy block particles" (One of the suggested companions) (https://minecraft.curseforge.com/projects/fancy-block-particles) sand storms are invisible. The only visual effect that appears is the fog color.

Must have been a "recent" change to break this.

Yep - recent change. Turn off the fancy rain and snow in FBP (the settings are in the Particle.properties file in the FBP folder) and it should work. FBP is hooking the weather renderer when this is enabled and that blocks DS from doing it's thing. Unfortunately this is something that I cannot fix.

Oh hey there.. I was browsing the internet and happened to come across this post..
I mean yeah.. it would be great if there was a list of weather renderers to which you could just add your renderer.

I was thinking the same thing. :)

That does sound like something Forge could do. Maybe pop a message over to their github?