 The wave rises from deep water on a sloped bottom and breaks over a very shallow reef, creating a massive and fast-moving surge of water that curls over. The waves are normally 6 to 10 feet high, but can exceed 20 feet. And one more fun fact, this event sets the record for farthest distance for an Olympic event from the host city, sitting 9,800 miles away from Paris. Kathy, Olympic surfing starts July 27th.