There could be dog schitt in that pile, too, which would also be slippery.

Yesterday, I rode my Fuji Cambridge, because my Super Course is currently disassembled. The Fuji is the only other ready-to-go bike I have with fenders. I plan to sell the Fuji, but the owner gave me permission to ride it. It is an extremely upright bike. My hands are right in front of my knees. The result is that my weight is all on the rear wheel, which makes the steering very light. I'm not sure if this gives me more or less traction, since there's barely any weight on the front wheel. Luckily, it's quite easy to steer this bike rather than leaning it, keeping it upright through turns.