Turnagain Arm, a long, winding offshoot of Cook Inlet, is home to a rare natural phenomenon - the moon-powered wave called a bore tide.
A wave is generated when the leading edge of an incoming high tide collides with the outgoing low tide in the long, narrow channels of Turnagain Arm, creating a choppy and turbulent wave front. When conditions are right, the wave can last for miles as it moves up the Inlet. At 10 to 20 miles per hour, the wave tumbles over the calmer outgoing tide, creating a wall of water cresting as high as 10 feet. There are 60 bore tides around the world. but few this large. For the hard core, it's a surfing phenomenon.
For a few days a month, the gravitational pull of the moon makes the bore tide big enough to surf. Braving frigid water temperatures and dangerously powerful ocean currents, an eclectic group of surfers has sprung up around a shared passion for chasing the wave. Unlike traditional surfing locations where wave after wave will roll toward the shore, these intrepid surfers have one shot. If they miss the wave, they will have a long float back to shore and an 11-hour wait until the next bore tide. If they catch it, they can ride for miles.
