"On Mount Shasta and at a growing number of national forests and parks across the West, climbers are taking the "leave no trace" ethic to a new level. In the past four years, climbers have hauled 10 tons of their own waste off Mount Shasta as the park tries to avoid the sight, stench and health threat of human waste.

"The policies grew out of necessity as rangers found themselves dodging droppings late in summer as the snowpack receded.

"'People are essentially leaving time bombs in the snow. When it melts they're right at the surface,' said Jon Nakae, wilderness manager for Mount Adams Ranger District in southern Washington. 'You would smell human waste later in the summer, or around the boulders you would find piles.'"