Sacramento Bee: Standing atop Yosemite’s tallest peak in August 1950, Hal Klieforth looked out across the Lyell glacier and marveled at how solid and unyielding it appeared. “It was like Grand Canyon or the Sierra itself,” the 81-year-old meteorologist said recently. “It had been there for many years and probably would be there for many more.” Today, as the boulder-strewn sheet of ice recedes in the summer sun, Klieforth is no longer so confident. “Now I guess there …