for championship skier chris davenport, skiing is more than just a pastime. >> skiing through powder snow, champagne power as we call it here in colorado, is almost an indescribable experience. you've got gravity pushing you down the hill, the snow is sort of coming up over your body silently, the air is cold, it's blue sky, and these crystals are sort of glistening in the air, it's almost an out of body experience. and that's the thing that makes skiers, gets skiers addicted to the sport. >> sreenivasan: but these days davenport is worried his sport is headed for a fall. >> you don't know if you're going to have good snow. you don't know if it's going to come early or late, or if the spring is going to become warm, and the season is going to end prematurely. we just don't have that dependability anymore. >> sreenivasan: those variations are what mark williams, a snow hydrologist at the university of colorado has been studying. >> in terms of climate change, the parameter, that's most sensitive to climate change, is snow. in particular we're starting to lose snow on the shoulders; th