No riding in the snow for me in general. So I totally understand the OP turning back in those conditions. I pushed it a bit today cycling in across the GWB. It usually still has some snow and/or ice even with the light dusting we got in NY/NJ yesterday. The commute today was ok since the roads were clear. Only scary point was the GWB south sidewalk ramp on the NY side. It had a thin sheet of ice on most of it. So I went ultra slow and kept a foot out of the pedal when I went down that part. For the rest of the bridge sidewalk, I usually use 90 psi on 700x23 tires and stay in the drops for lower center of gravity and more stability.