Hello Karol,
unlike CoH2, CoH1 doesn't feature specific snow textures, neither does it provide it seperate snowfall settings. What's typically done though to reproduce the snowy environment of the Eastern Front is the usage of sand tiles combined with an array of other sand textures (splines and splats alike). The secret behind all that comes now though - you must have an atmosphere setting that doesn't let sand look like actual sand, the key is to change the settings in order to let the sand seem white or even white-blueish. Here's an array of winter weather setting you might want to try - just place them in "C:\Users\%username%\Documents\My Games\Company of Heroes\ww2\Data\Art\Scenarios\Presets\Atmosphere\" and load them in WB's Atmosphere Properties!
If you do have any further questions, feel free to ask them!
Best regards,
Max, Lead Level Designer
