Black Ice...
Really sucks. This morning on my fixed gear, about 6:45, I slowed to turn onto the lake shore bike path here in Toronto. Before I knew what was going on, I was on ground. Not hard, but hard enough. I started laughing, checked my bike, everything's ok, ride away. Now, my L-bone hurts. Owie.
Black Ice=Double plus ungood. Especially on road tires.