Viewing The Bore Tide

The Bore Tide

The bore tide is a huge wave or series of waves that advance down Turnagain Arm in a wall of water up to 10-feet high. It’s a dramatic show of nature’s power that’s easy to see using our guidelines below.

What Are Bore Tides?

The bore tide is a rush of seawater that returns to a shallow and narrowing inlet from a broad bay. Bore tides come in after extreme minus low tides created by the full or new moon.

Bore tides occur all over the world—there are around 60 of them—but only a few are large enough to make a name for themselves. One in China, for example, stretches almost 30 feet tall and travels more than 20 miles per hour. Alaska’s most famous bore tide occurs in Turnagain Arm, just outside Anchorage. It climbs up to 6 – 10 feet tall and can reach speeds of 10 to 15 miles per hour. It takes not just a low tide but also about a 27-foot tidal differential (between high and low tide) for a bore to form in Turnagain Arm.

What's So Special About the Turnagain Arm Bore Tide?

Well, it’s huge—one of the biggest in the world, actually. Also, all other bore waves run up low-lying rivers in more southerly latitudes. The Turnagain Arm bore wave is the only one that occurs in the far north and the only one bordered by mountains, making it the most unique and most geologically dramatic bore tide in the world. It’s also amazingly accessible: you can see it by road along its entire 40- to 50-mile length. And it’s a wildlife-spotting opportunity: harbor seals often ride the tide into Turnagain Arm. Beluga whales may come in a half hour or so later once the water gets deeper.

Where to See The Bore Tide

Drive south from Anchorage about 20 minutes to Beluga Point. The best viewing is from there all the way down to Portage, about an hour south of town. There are five highway pullouts along this stretch. The highway traverses the shoreline along the flats, giving you a real sense for the power and scale of the bore tide. For a wider but more distant view, you could climb Bird Ridge about 30 minutes south of town. Another option with even better viewing is the town of Hope, across Turnagain Arm, but it’s a good hour-and-three-quarter’s drive from Anchorage.

WARNING: Don’t walk out onto the mud flats—people have died by getting stuck in the glacial silt and being drowned by the incoming tide!

When Can I See The Bore Tide?

Tidal bores occur on Turnagain Arm every day, but most produce relatively modest waves. In theory, you would expect the largest bore tides to occur on tides with the highest tidal differential. In reality, they tend to occur just before or after that. This means your chances for seeing a large bore are best during the five-day window that surrounds the new and full moons. Get the dates for new and full moons from the NOAA site.

During this window, get the times for the two Anchorage low tides occurring each day either from tide charts available at gas stations or from this site. The bore tide should reach Bird Point 2 hrs and 30 minutes after Anchorage/Fire Island low tide. If the wind is blowing down the arm (the way it always blows—just look at how the trees grow), add another 10-15 minutes. You can watch the bore go by at the first pullout, then drive your car down a pullout or two and watch it come by again. It takes over five hours for the bore to travel from the mouth of Turnagain Arm to the end of it.

Extreme low tides promise the largest bores because of the amount of water rushing back into the inlet. Also, tides tend to be greatest annually at the equinoxes (March and September), particularly during the fall equinox, so look for especially strong bore tides if you’re traveling then.

Find Bore Tides Fascinating?

	Customized tide tables for Anchorage. Powerful but a little complicated.
	Watch a video of a large Chinese bore tide (larger than Turnagain Arm's).
	Surfer riding Turnagain Arm's bore tide.
	Learn about the world's bore tides.

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Alaska Bore Tides