The image on the right shows the effect of tfErosionSnow on the landscape, with a tfNoise filter applied.
tfErosionSnow, Properties tab menu settings.
This is set to Thermal Weathering Mode, by default.
The other Mode settings are: Hydraulic (2D Particles), Hydraulic (X-Particles), Coastal and Snow.
These other Mode settings are dealt with in more detail in their own dedicated pages.
Eroding a terrain with snow will smooth out the snowy areas while preserving the precise topology of the areas that remain free of snow.
Sometimes the snow effect looks better when using rather subtle values for Radius and Lift than, instead, computing it multiple times.
This parameter controls how often the snow erosion is computed.
The more iterations, the more snow you will have.
Radius is at the same value of 10 for each of these terrains, with Iterations set as 1 on the left, 3 in the center and 10 on the right.
The radius controls how much of the terrain's detail is retained after the snow’s erosion.