YOSEMITE NATIONAL PARK, Calif. -- On a June day, Frank Gehrke and Vince White strapped on their cross-country skis and glided across the wintry landscape of Dana Meadows in Yosemite National Park. The surrounding peaks were wrapped in snow, the breeze crisp enough for a hat and gloves.
The men screwed together four sections of a hollow aluminum tube White had carried on his backpack. With a vigorous twisting of a handle attached to the cylinder, he drove it into the layers of snow. It didn't hit dirt for another 7 feet.
After pulling up the snow-filled tube, White weighed it to gauge the water content. The Dana Meadows snowpack had enough water to form a 3-foot-deep lake.
From the Sierra Nevada and the Cascades to the northern Rockies, much of the West's high country remains buried under a thick snowpack that is filling reservoirs and engaging dam operators in a nerve-racking balancing act as they watch for jumps in temperature that could turn all those scenic piles of white into raging floodwaters.