Snow, Sun, and slipping on asphalt

While winter storms batter New York, my sister Adrianna and I have been taking advantage of the warm and sunny weather here in Washington State to play outside on an apparatus called the skateboard. Since neither of us are up to actually keeping our balance standing up on it, we sit down on it and roll down our neighbors' driveway (which slants downward) at great speeds. We have another wheeled device that actually has a proper steering mechanism with handlebars, that is painted red. (I favor it personally.) I was going down our neighbors' driveway just this morning on the vehicle and, fearing that I was going to ram into a decorative wall, attempted to bail off unsuccessfully, leaving my knee dragging on the ground as I hurtled downwards. I managed to get off just in the nick of time but with a bleeding knee from the asphalt. Talk about wounded.