A Cowichan Valley woman is warning other trail users to watch their steps after being impaled by a caltrop on a trail off Gibbins Road. Caltrops present a serious safety hazard to the public. They have a spike pointing upward no matter how they land after being placed or tossed. Known as “area-denial weapons,” they look like toy jacks — only larger and much sharper. Not only can they puncture bike and vehicle tires, but they can also cause serio…