Underwater cave diving is a risky business.
Environmental anthropologist Kenny Broad and one of his fellow researchers-cum-explorers know this for a fact after experiencing an “underwater avalanche” — which is when sediment from the walls of the cave collapses in around the divers.
The harrowing experience, which took place in one of the Bahamas’ mysterious blue holes, was captured on video. National Geographic uploaded the footage to YouTube last week.
See Huffpost Science