Every summer, surfers from across Southcentral Alaska flock to Turnagain Arm in hopes of riding a bore tide. On one of the biggest bore tides of the summer, a few lucky surfers and paddleboarders managed to do just that.

The bore that sloshed Turnagain just before 5 p.m. on Monday brought out a pack of adventurers, each hoping to catch some white froth for ride up the arm.

Bore tides are nature's true "tidal waves" -- occurring when incoming tide builds into large dramatic front as it rushes into a narrow channel or river against the outgoing current. Turnagain Arm is the only U.S. locale where the bores strike with regularity, although bores can churn up Knik Arm too. The just-right alchemy of wind and current during a minus tide and a full moon can spawn 10-foot bores that travel as much as 20 mph up the channels.

Read the full story and check out a slideshow of bore tide surfing.