Flying over the massive Glacier Bay landslide

News of the mammoth landslide that buckled from a mountaintop and spilled out onto the Lamplugh Glacier last month in Glacier Bay has traveled around the globe and back again.

It’s about 6 miles long and more than a mile wide, and it rocked the earth with the equivalent force of a magnitude 5.5 earthquake. That’s hard to visualize, so I took a ride with pilot Paul Swanstrom to see the slide myself.

It’s 2 p.m. on a sunny Thursday. The wind is calm and we’re told it’s perfect flying weather.

In the stout, shiny 1956 de Havilland Beaver, there are six of us, plus Swanstrom. He owns Mountain Flying Service with his wife, Amy, and was the first to discover the slide on June 28. Today, we’re heading to the site, cruising along at an easy 115 mph with gasp-worthy vistas as far as the eye can see.

“We’re going on an East and West Arm Glacier Bay flight from Haines, over the Chilkat Mountains,” Swanstrom says.

As we make our way over and around the craggy, snow-capped peaks, Swanstrom says he’s not surprised the story of the slide has taken off. But he says he hasn’t had much time to really stop and absorb the media attention.

“I’ve been pretty busy to even understand it,” he says.

His business has gotten calls from Fox News, and there was something in the New York Times and the Alaska Dispatch News.

“But we’ve been so busy flying that I haven’t really looked at any or taken the time to read them.”

As we buzz along, Swanstrom identifies peaks and glaciers. He’s got a story or a nugget of information about most all of them. And his captive audience is eating it up with eyes wide and mouths agape.

After about 30 minutes, the slide comes into sight. It is humongous. It looks fluid, like thick black paint spilled on a white canvas. The contrast is stark and the size is simply astonishing.

“Whoa, look at that!” says KHNS sound engineer John DeRosa, who was along for the ride. “Wow, it just keeps going. How is that possible? How is it possible that those rocks moved that far?”

The rest of us are speechless. Swanstrom pilots closer around the top of the mountain to the breakaway zone. Dust is still rising from the area because chunks and boulders are still sloughing off.

“You can see how it bulldozed snow up at the bottom of it there,” Swanstrom says.

“This is remarkable, Paul! This is remarkable!” John says.

Colin Stark is a geophysicist at Columbia University’s Lamont-Doherty Earth Observatory in New York. He says the amount of force in this slide totaled 28 giganewtons and spit out around 120 million metric tons of rock debris. He says this is the largest recorded slide anywhere in the world this year.

Stark just got back to New York from Southeast Alaska. He visited the site last week with the help of Haines pilot Drake Olson. Stark says there were two big discoveries upon inspection of the slide. One is that the slide is still very much active.

“There’s been rock falling 24/7″ since the big slide, Stark says. “It has not stopped. It’s quite amazing. When you look at the lower slope from the ground, you can see individual boulders crashing down that are probably the size of a very large car.”

Those smaller slides, which are still huge, mind you, create little plumes of dust, which rise and gather into a bigger dust cloud over the area. Stark says the constant slides are really loud. They sound like fast flowing streams, he says, but “crunchier.”

The second detail that Stark noticed was that when the slide let loose, it did so with such unbridled force, that it pushed rock and dirt up the sides of the valley almost 300 feet. So, it’s left a ring on the flanks of the valley. Like a ring of grime leftover in a bathtub.

“Rock and ice slide, with all that momentum it was going down the glacier, but when it hit the valley walls it climbed up, very steeply up the rock wall and then slid back after reaching a maximum,” Stark says. “And then what you see now is the remnant of the highest point that the dirt got to. And it’s clinging, but it won’t be for long, because we could see rock fall coming off there, too.”

Stark says these slides are becoming more prevalent in the area, which, as a researcher is good for him. But not great for the rest of us in terms of what it could mean.

“Glacier Bay and St. Elias together are the most active rock avalanche places in the world,” Stark says. “So, you guys have the worst of it. Or the best of it, depending on how you look at it. Because of glacier retreat and warming, the situation is getting worse. Or from my perspective, better.”

Back on the Beaver, we circle around the peak and continue to marvel at the epic event still moving beneath us. Eventually we head back to Haines trying to really understand what we just saw. Tourists are now requesting the flight over the landslide as the news travels. But Swanstrom says, even though he flies over it a few times a day he never gets tired of looking at it.

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