For my racing level I made a sand cloud particle system in cascade in
UE4. To do this I used a Sub UV set material and several emitters.
( The particle in the level in the cascade editor, you can see which nodes are used here)
(The Sub UV set used i the level)
The first emitter is for random sand specs flowing within the cloud so that it may take on the appearance of sand, the next three are layers of cloud, I originally only had two of these emitters but when I brought the particle system into my level there wasn't enough contrast for the particle system to be noticeable so I tweaked it from there, the last emitter is to give the effect of sand particles running along the ground of the particle system.
The sand particle system initially exists within my level, but over time more sand clouds are triggered through laps in the race.


























