It seems C-band is better in the snow as well as the rain judging by these pics. My 4-foot Fortec kept receiving ARCS from 139W at 7.0 dB even though it had a little snow on the dish/LNBF. The Ku dish stopped receiving.
C-band is much less susceptible to precipitative attenuation than is Ku. It was originally chosen for sat and terrestrial links because of its rain stability. Thus a better ability to get past snow buildup doesn't surprise me.