I'm trying to understand what causes this effect in SF2:I in the screenshot below. I only see it when at altitide 12K or higher. It comes and goes, appearing as the plane moves or the angle of view changes. It seems to happen only when looking through the clouds at a certain angle, roughly 45 degrees.  
  
This occurs after modding environmentsystem.ini. I took a default one and only modded broken clouds, nothing else, with the following: 
  
[CloudsBroken] 
MaxClouds=100 
MaxCloudParticles=64 
3DCloudMaterial=CloudMaterial 
3DCloudHorizontalSize=4500.0 
3DCloudVerticalSize=1500.0 
3DCloudSizeDeviation=0.3 
3DCloudParticleDensity=2.6 
ParticleSize=440.0 
ParticleSizeDeviation=0.3 
MinBaseAltitude=600.0 
MaxBaseAltitude=2900.0 
UseBottomRow=TRUE 
MaxVisibleFactor=0.6 
Transparency=0.9 
  
The very low MinBaseAltitude (600) may appear to be the cause at first glance but even when I put the value at 2000 I get the same effect. I suspect the high 3DCloudParticleDensity value might be the cause but I don't understand how it could. Even if so, I hope there is a workaround because I prefer I far higher 3DCloudParticleDensity than the one I have here. 
  
Anyone have any ideas?