hidden inside air pockets in the ice. it's relatively common for small pieces of the glacier to calf or break off. it's one of the reasons the tourists visit the site. but spectators gathered on the lakeshore are on the verge of witnessing a release of a staggering amount of glacial tension. as they stand almost beneath it, the face of the glacier crumbles before their eyes. the crashing ice sends soring waves directly to the bystanders. it all happens in seconds. there's no time to react. >> there's one person who is not moving at all, even after the biggest piece falls in. my impression is he's still trying to take pictures. >> the powerful wave slams a dozen victims into the freezing lake, and lashes them against the rocks. >> the water was very cold. there were beaten by the wave and taken away. they could have hit their head on the rocks. >> it's a terrifying moment,