Bore Tides: Against the Current

In a few places on Earth, local geography and tidal conditions align to cause a phenomenon called a tidal bore: An incoming high tide collides with the outgoing tide in a narrow channel, generating a turbulent wave front. The shape and size of a bore tide varies greatly, from gentle undulations to a powerful single wave rolling over any obstacle in its path. China's Qiantang River claims the highest bore, up to 9 meters (30 ft) high. In other places, such as Alaska's Turnagain Arm, Brazil's Amazon River, and the River Severn in the UK, surfers paddle out and try to catch the bore tides for a quick trip upstream.

Read more
Hints: View this page full screen. Skip to the next and previous photo by typing j/k or ←/→.

Most Recent

  • Chensiyuan / Wikimedia Commons

    The Spectacular Seda Monastery

    High in a treeless valley in China's remote Garze Tibetan Autonomous Prefecture lies the largest Tibetan Buddhist school in the world.

  • Lucy Nicholson / Reuters

    An Oil Spill Fouls the California Coastline

    A pipeline burst yesterday, spilling an estimated 21,000 gallons (79,500 liters) of crude oil into the Pacific Ocean near Santa Barbara.

  • USGS / Robert Krimmel

    The Eruption of Mount St. Helens, 35 Years Ago

    On May 18, 1980, 35 years ago today, an earthquake struck below the north face of Mount St. Helens in Washington state, triggering the largest landslide in recorded history, and a major volcanic eruption that scattered ash across a dozen states.

  • Taylor Weidman / Getty Images

    Photos of the Week: 5/9-5/15

    This week, we have photographs of jet-men flying over Dubai, a spring snowstorm in Colorado, archery in the Amazon, airstrikes in Yemen, rebuilding in Nepal, migrant ships adrift in the Andaman sea and the Mediterranean, B-25 bombers over Washington, D.C., the Victory Day parade in Moscow, and much more.

Join the Discussion