A kayaker rides the biggest bore tide of the summer as it roared into Turnagain Arm south of Anchorage, Alaska, on Tuesday.

The biggest bore tide of the summer roared into Turnagain Arm south of Anchorage, Alaska, on Tuesday, June 5, 2012. Here a kayaker awaits the bore tide to ride it. Bore tides can happen all over the world, but Anchorage's Turnagain Arm and Knik Arms are the only places in the United States where they occur regularly, according to Michael Lawson a meteorologist with the National Weather Service in Anchorage.

Pat Keller competes in the Men's K1 of the 2012 U.S. Olympic Trials for Whitewater Slalom at the U.S. National Whitewater Center on April 13, 2012 in Charlotte, North Carolina.

Scott McCleskey (L) and Dave Hepp (R) navigate a rapid in the men's C2 during the U.S. Olympic Trials for Whitewater Slalom.

Michael Rudnitsky reacts after his run in the men's K1 of the 2012 U.S. Olympic Trials for Whitewater Slalom.

Maxime Leboeuf competes in the men's K1 of the 2012 U.S. Olympic Trials for Whitewater Slalom at the U.S. National Whitewater Center on April 13, 2012 in Charlotte, North Carolina.