Tourists can be seen running from the surging water. Mantler told CNN they were expecting this to happen and no one got hurt — or even wet.
As the piece of glacier cracks off and slides down into the icy waters, things almost seem to move in slow-motion.
“While calvings are fairly frequent at this time of the year, this was an extraordinarily large event and much closer to the shore than usual, which is why it was such a close call,” Mantler said.
