Probing for security. Mountaineers crossing a glacier in the spring do something that looks odd from a distance. Before each step, they reach down and stick the butt end of their ice ax into the snow. They are probing for…
Probing for security. Mountaineers crossing a glacier in the spring do something that looks odd from a distance. Before each step, they reach down and stick the butt end of their ice ax into the snow. They are probing for…