Natural ice on lakes is usually rougher, because it typically has snow on top that partially freezes on. Esp if there's frequent melt+refreeze. There's the odd

Natural ice on lakes is usually rougher, because it typically has snow on top that partially freezes on. Esp if there's frequent melt+refreeze. There's the odd winter where you get ice smooth and snowless like a rink, but rare. Used to walk around on ponds and lakes quite a bit as a kid.