The Shadow of the Rock

There's a well-documented phenomenon among desert hikers in places like Arizona's Sonoran Desert or Israel's Negev wilderness. When the afternoon sun pushes the air temperature past 110 degrees, the ground temperature on exposed sand can reach 160 degrees or higher. But step into the shadow of a large sandstone outcropping, and everything changes. The temperature in that shadow can be 30 to 40 degrees cooler than just a few feet away in the open sun.…