We've all been there: We hit an unexpected current and it can be unpleasant — and down currents can be frightening. Diver John Hoover had an unnerving experience during a dive off Maui's Nakalele Point.

The massive vortex and powerful surge was probably caused by strong surf. Hoover survived unscathed and uninjured. You be the judge: Did he take the ride intentionally or unintentionally?

A vortex is a whirling mass of fluid or air. Synonyms are whirlwind, cyclone, whirlpool, gyre, maelstrom, eddy, swirl, spiral, black hole — but by whatever name you call them, it can be scary when you're caught in one unintentionally. Keep your head, hold onto your reg, and ride it out. If you're caught in a down current, swim perpendicular to it until you're out of it, and then ascend safely. It can be dangerous to be in the water when the ocean is throwing unpredictable current at you.

Video courtesy of MrTeamZissou

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