MAMMOTH LAKES, Calif. - Three members of a ski patrol died after two plunged into a volcanic fissure at the Mammoth Mountain resort and the third fell trying to rescue them, a resort official said. Four other would-be rescuers were hospitalized for exposure to carbon dioxide but were doing well, said Rusty Gregory, chief executive officer of Mammoth Mountain Ski Area. The patrol team had been on the mountain after a snowstorms checking on a fence surrounding a fumarole, a natural vent that releases volcanic gas from deep within the Earth, Gregory said. "It's not like they were out there...