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Last Update: May 5, 2005 8:19 AM

Unusual Turnagain Arm tide has attractions and dangers

Thrill of the Bore

Imagine driving south on Saturday for a perfect spring picnic on Turnagain Arm. Shake off that winter weariness, pack a baguette and a jar of Nutella, and find a quiet overlook where you can toss out a blanket and watch the sun sizzle snow off the mountains.

It's a relaxing picture, but there's one more reason to make the trip this weekend. Grab your binoculars, and for goodness' sake, stay out of the water. The new moon is here, and it's bore tide time.

Like an army marching 25 miles up Turnagain Arm, the bore tide advances in one cascading wave -- a wave that can reach 6 feet high and carry surfers for miles. The Arm, with its shallow, narrow, gently sloping basin, is perfect for this rare natural phenomenon. And when you shove a huge volume of water into this basin twice a day -- Turnagain Arm and Cook Inlet have some of the most extreme tides in the world -- what you get is the only regularly occurring bore tide in the United States.

Mark Johnson, a marine scientist at the University of Alaska Fairbanks, sums up the effect by saying, "It's like water in the bathtub: When you move just right, the water really starts to slosh."

Watching the bathtub fill up can be quite a sight.

I was there for the last new-moon bore tide. It was a Sunday evening, and the Beluga Point pullout on Seward Highway was crowded with cars and the occasional recreational vehicle. Parents and small children clambered over rocks at the shoreline. A man on a small knoll unfolded a kite, taking advantage of the stiff breeze. Older people basked in their cars.

It was two days after April's new moon and about an hour before the tide would recede to minus 2.4 feet, one of its lowest points this spring. Many people at the pullout knew that sometime around 5:15 p.m., the returning water would rush past Beluga Point in what they hoped would be a prime showing of the bore tide.

As I stood on a small cliff watching the water below me grow more turbulent by the minute, a smiling Alaska Native woman approached, trailed by a gaggle of long-haired little girls.

"What did Grandma say we were going to see?" she asked them. "The bore tide."

Lily VanFleet knows Anchorage-area waters well. Her extended family goes out by boat every year in search of fish and -- when they can get the permits -- beluga whales.

Though she has traveled widely in Cook Inlet, VanFleet generally avoids Turnagain Arm. An Inupiaq Eskimo, she pointed out that Athabascans native to the Anchorage area have known of the Arm's danger for generations. "They knew that mud was bottomless."

Bottomless indeed. According to Anchorage engineering geologist Bob Dugan, a California oil company once drilled a test hole in the mud flats near Girdwood. When they called it quits at 915 feet, they still had not hit bedrock.

Surprisingly, much of the Arm's notorious sludge isn't local. Studies show that the tide carries in sediment from such distant points of origin as the Matanuska, Knik and Susitna rivers.

Combined with a tide that can reach speeds of more than 15 mph, the silty sand of Turnagain Arm can be deadly. I was raised on the Arm's most tragic story and have never once strayed onto the mud flats because of it. In 1988, a young woman got stuck in mud as she tried to push her husband's entrenched ATV off the flats. Despite hours of heroic effort, her husband and a crew of rescue workers failed to free her. The woman drowned when the tide came in.

The swirling brown water off Beluga Point does look treacherous, but the afternoon sun, a friendly companion and the fact that we're both safely onshore made for a cheery atmosphere. VanFleet grinned infectiously and hugged me when I told her I grew up in Palmer. "And you've never seen the bore tide?" she exclaimed.

It's true that until that weekend, I hadn't -- except maybe once. Years ago, I hiked up Bird Ridge with friends on a hot July afternoon. On a break, I leaned back into the steep slope and squinted down at the water far below me. The sun was blinding, but I could have sworn I saw what looked like a fine white thread strung out across Turnagain Arm. Could that have been the bore tide?

It probably was, according to people I've asked.

The wave is not hard to spot, especially if you often drive or hike along Seward Highway. Former Chugach State Park ranger Doug Fesler has watched it many times. He once saw a bull moose tread into the water in front of the oncoming tide. Panicked, the moose tried to outrun the 3-foot wave. Even after it was swept up, the moose struggled on.

"He was running on tiptoes on the mud, and then he hit a channel where it was deeper," Fesler said.

Within 15 minutes, the moose had gone under for good.

Another time, Fesler was headed home in the truck he drove as a ranger when he spotted an orange tent pitched far out on the mud flats. Knowing that the tide was coming in, he started yelling into the truck's megaphone until, he said, "first one head popped out, then another." At Fesler's urging, the three campers in the tent packed up and headed to shore, understanding their peril only as the tide finally approached.

"You could see the wave coming in the distance, and they started jogging and then they started running," Fesler said. By the time the trio made it to the last channel, they were up to their waists in the current.

Yet Alaska's bore tide does not hold a monopoly on danger. Bore tides run in more than 60 places on Earth, perhaps many more. The largest, which runs up the Qiantang River in China, was traditionally called "the dragon" and can reach heights of 29 feet and speeds of 24 mph. On a trip to the island of Borneo, the English novelist W. Somerset Maugham nearly drowned in a ferocious tidal bore that locals call "the benak." In France, the "mascaret" of the Seine River menaced hundreds of ships in the 18th and 19th centuries. (It nearly disappeared in the 1960s after canal construction and the dredging of the Seine estuary.)

Navigation is also tricky in Turnagain Arm, where it's rare to see anything much larger than a kayak. One notable exception was a few years back when a Homer company won the contract for a big construction project on Seward Highway. Transportation of materials to the site was an expensive proposition that likely drove up the estimates of unsuccessful bids. Aside from the already high cost of delivering materials to a remote site, springtime axle load limits meant that whoever took on the project would have to either pay for extra trucks or delay work until after breakup.

But the Homer contractors thought they had a solution. They flew a helicopter over Turnagain Arm at extreme low tide to chart the deepest channels using the global positioning system. Then, during several high tides, they sent in a landing craft to follow the deep channels, deliver the goods and get out before the retreating water left the vessel high and dry. Though the tide caught the boat on its first attempt, the idea worked. As Fesler said, "They used Alaska know-how to pull off a coup."

In spite of the hazards, many hardy souls have ventured out in much smaller vessels to surf the fiercest bore tides. John Markel has been riding the tide in his kayak for more than 20 years. The challenges of not only catching the wave -- a one-shot deal unless you get out of the water, drive past the wave on the Seward Highway and get back in -- but also finding the best channels in which to surf it have kept his hobby fresh.

"Some areas are good for surfing and others aren't, and those areas change all the time according to bottom conditions," Markel said.

Advice varies, but most surfers agree that negative low tides, a strong southeast wind coming out of the Arm, and narrow channels where the wave concentrates make for the best bore tide surfing. All agree that only very experienced kayakers and surfers should attempt it.

The tide that VanFleet and I watched that Sunday in April was not big enough for surfing. When the bore tide finally rounded the point just offshore, it did so at a stately ripple. Through my binoculars, I could just make out a frothy wave less than a foot high farther out.

No one seemed to mind. One of VanFleet's granddaughters ran up to give her a white gull feather. Couples sat on the rocks and gazed out at the ocean. Cars pulled out of the parking lot, and new ones pulled in, their owners unaware they had just missed the bore tide.

Was I disappointed? Not really. From shore, the bore certainly lost some of the mystique that it shimmered with when I saw it from high on Bird Ridge. But this was due, I think, to my more mundane, drive-up, middle-distance perspective from the highway. Maybe the best bore tides are the ones you experience after sweating up the side of a mountain or paddling out in front of the oncoming wave.

As Markel said, "It doesn't look quite as interesting from the road as it does when you're right under it."

Sarah Lemagie lives and writes in Anchorage.


How to plan your bore tide sighting

Planning a bore tide sighting is easier than you may think. With some general knowledge about bore tides and a tide table for Anchorage, you can witness bores in Turnagain Arm throughout the year. The following are guidelines for making your bore tide field trip worthwhile.

• Choose the new or full moon periods each month to catch extreme tides.

• Once you identify time periods with extreme tides, look for a day when the predicted tide range for Anchorage includes large negative values for low tide.

• Find yourself a good vantage point along Seward Highway for watching the tidal bore, and use the chart above to determine when the bore tide should arrive. (Tidal flow is strongest halfway between low and high tide, which may make for especially good bore tide viewing at points midway up Turnagain Arm.)

• Knowing that the bore travels about 10 to 15 mph, you can estimate when it will be at other locations in the Arm.

• Be at the vantage point at least a half-hour before you expect the bore to arrive.

• The water will seem calm just before the bore's arrival.

• Look and listen for a series of undulant waves two to three feet apart. They may be breaking along the shore or across a channel or channels.

• Note: The bore tide can be dangerous. To be safe, stay out of the water and away from the shore shortly after low tide.

Source: "Alaska Bore Tales: A Local Guide to Bore Tide Sighting," a pamphlet put out by the National Ocean Service office of the National Oceanic and Atmospheric Administration in Anchorage and available at the Anchorage Tourist Center log cabin downtown.

Photo by Erik Hill / Anchorage Daily News archive 2002
Click on photo to enlarge

Colin Brown of California caught a short ride on the bore tide near Bird Point in 2002. "It's like a long ocean wave," he said. "It was cool!"