Calving glacier sends waves across Portage Lake

Published: Mar. 7, 2019 at 10:33 PM AKST
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On Wednesday afternoon, a beautiful day at the frozen Portage Lake was interrupted by a force of nature.

Around 3 p.m., the glacier calved, crashing through the ice at the glacier’s face, cracking the lake's surface ice up to a third of a mile away.

Paxson Woelber was on the ice with friends about a quarter of a mile from the glacier's face taking photos when it happened.

"People describe it as a sound of a jet engine or like a bunch of trains colliding. There's a million metaphors and none of them quite capture what it is," Woelber said. "We knew that we were far enough away that we weren't going to go in the water, but we knew that the ice was probably going to crack and move with the swells. So we just tried to stay pretty calm and just ride it out."

Woelber captured video showing waves lifting up newly fragmented pieces of ice.

"It was really unsettling, but we'd been out there quite a few times so I think that we had a pretty good sense of what was going to happen and where we'd be scared, but safe," Woelber said.

The lake is within the Chugach National Forest, and the forest service asks that all visitors prioritize safety.

"We do keep an eye on trails and conditions of the forest. The forest is vast of course, over 5.4 million acres, and we don't technically monitor the lake as to how many inches of ice,” U.S. Forest Service spokesperson Alicia King said. ”We actually recommend that people not go on the lake.”

Portage Glacier is one of several glaciers within Chugach National Forest, but its proximity to Anchorage means it sees more visitors than most of the other glaciers.

"When a glacier calves, sediment, ice and water are released from that glacier area, and in particular for Portage Lake, they meet so that the unstable conditions of the lake sometimes cause buckling and ripples to come from the impact of that glacier," King said.

King says that visitors should check the avalanche forecast and weather conditions before making a trip in to national forest lands.

"We like for people to go out and explore. It's your forest. It's your public land, but we ask that you be safe and really think about safety first as you do anything," King said. "So when you're out in Prince William Sound and a glacier calves, the waves come along and can rock the boat. So if you imagine a frozen lake that may not be that frozen, or that has water underneath it but may be slightly frozen on top, the same thing is going to happen and you get the cracking and the water and the ice to do that buckling. It's really cool to watch, but watch it at a distance."

Since Wednesday's calving was during the week, relatively few visitors were on the lake, and none were close enough to the face of the glacier to fall into the water.

This past weekend however, dozens of people took to the lake for skating and to view the glacier, and some put themselves in riskier positions.

"We were watching people walk right up to the face of the glacier. People were taking their kids in stroller right up to the face and standing directly under the calving face of the glacier. It's just incredibly lucky that this even didn't happen when they were doing that," Woebler said. "I think it's almost certain that some of those people would not have survived what we saw, so that's a very sobering and very intimidating face to confront."

Woebler says he still feels safe skating on frozen lakes when the conditions are appropriate, but hopes that other people recreating on the lake are mindful to minimize risks.

"Portage Lake or Eklutna or any of these big lakes, they're not categorically unsafe to be on, but you have to be really situationally aware and know when there are hazards, know how to identify hazards, know how to mitigate the risks," Woebler said. "Most importantly in this case, just understand that there could be relatively little risk half a mile from the face of a glacier, but extreme life or death risk right at the face."