Melting permafrost intensifies sinking problem in Nome
Unstable permafrost is nothing new to the Arctic and annual frost heave is a perennial construction concern, but recent years have seen a marked uptick in melting ground that has forced builders in Nome and throughout the region to rethink some of the ways they build structures to last.
Jim West Jr., business owner and chair of the Nome Port Commission, has spent his entire life in Nome, and shoring buildings up as they settle has always been an important part of life. “But I’ve noticed here that in the last five years, it’s definitely getting worse,” he said.
As the climate warms considerably in the Arctic, more permafrost softens and melts, causing buildings and infrastructure that had been relatively stable to start sinking in unpredictable ways. The National Snow and Ice Data Center reports that there is now about ten percent less frozen ground in the Northern hemisphere than there was in the early 1900s, totaling to about two million square miles of melted ground.
While the process of permafrost melting is slow, even small changes can be noticeable. In Nome, the changes are clearly reflected in the fact that settling structures are needing increasingly close and costly attention.
West said that the Nome port pad was put in decades ago and promised to last a long time, but the underlying permafrost is melting. As that ice melts, they’ve had to fill in with sand, and over the years it’s taken more and more to keep the pad level. “And it’s been 35, 40 years since that pad’s been built,” West said. “The warmer it is over a longer period of time, it’s going to melt faster.”
Scot Henderson, CEO of Bonanza Fuel, said he’s been experiencing similar troubles at the tank farm near the port. “We’ve had a fair amount of settling over the years, but in the last couple years it seems to have been a lot more significant,” he said. The key to avoiding serious problems was early detection, Henderson said. Bonanza uses a satellite-based warning system that measures 100 points around the tank farm every six months, identifying potential problems before they become visible to the naked eye. Once an issue is identified, they can build supports to shore up the structure or fill more gravel or dirt underneath it. But that comes with a significant cost, and sometimes it’s just not worth it. He pointed out a garage building on the port pad that’s been experiencing so much settlement in recent years, it’s just not cost-effective to keep leveling it. Next summer, Bonanza plans to demolish the building altogether and build a different one on more solid ground.
He added that the issue was not likely to get any cheaper to deal with as time goes on, and the increasing cost of shoring up the tank farm can even cause the price of fuel to go up. “This is not a small expense,” he said. “It’s a warning to the rest of the state and the nation that climate change is very real, and we have to deal with it.”
The melting causes issues for city infrastructure, too, as underground water pipes lose their structural support. Ken Morton, assistant manager and utility engineer at Nome Joint Utility System, said they’ve noticed an uptick in settling, but they’ve been prepared. “I don’t have the sense that what we’re seeing now is at the same extent that it was 20 years ago,” he said. “But that is certainly part and parcel with building out here, at this point.”
In the 90’s, NJUS started investing in stable bedding for all its new water and sewer lines to protect against settling, and Morton said it’s paid off. Most lines built in the last two decades have been holding up well. But they still face challenges with service lines that go out to private property and older mainlines from the 80’s.
Solutions to the problem exist, but cost can be a major hurdle. Some buildings in Nome like the Bering Straits Housing Authority building and the Covenant Church use multipoint space frame foundations, which can be fine-tuned to accommodate the shifting ground beneath. But adjusting them takes specialized labor and heavy equipment.
If bedrock is accessible, builders can also install pilings that root the building to the rock beneath the permafrost, protecting it from shifts. That’s the strategy used by Norton Sound Regional Hospital’s new 20plex, West said.
But the deeper the bedrock, the more costly that strategy is. And in most places, “the average guy isn’t going to be able to drove a piling all the way to bedrock,” West said.
Still other buildings use an underground coolant system to keep the ground underneath them frozen and stable, even as the ground around them melts. The Bonanza Express building has a passive cooling system, where metal poles conduct heat out of the ground and keep it cooler later in the year, Henderson said.
There even exist systems that actively keep the ground frozen by pumping coolant through it like a giant freezer. But, like other hightech solutions, “that costs money,” West said. “Lots of money.”
Aaron Cooke, an architect and program manager for the Cold Climate Housing Research Center, CCRHC for short, at the University of Alaska Fairbanks, has been looking into methods to deal with settling more cheaply.
“The methods used to be if the ground was frozen, keep it frozen. And if the ground was thawed, keep it thawed,” he said. “But that’s not really true anymore. Now, even if we do everything right with our foundation and our insulation, the ground could thaw anyway, because of what’s happening with larger climatic shifts.”
He said different climate models predicted different rates of melting, and that right now scientists didn’t have a method of predicting exactly what would melt when. So, in the face of that uncertainty, his priority is flexibility.
Many homes in Nome are set on long beams that require constant shimming to keep them level, he said, but the CCRHC is working on an alternate system using simple adjustable jacks, like modified car jacks, on the four corners of the home.
The idea is to create a stable structure that can be easily and cheaply adjusted by the resident without any specialized labor or heavy equipment. Cooke said they’re planning on building a test model in Mountain Village this coming construction season.
Another way to cope is to just build somewhere different. In Nome, that means close to the beach, where the ground is permanently thawed, or closer to Anvil Mountain, where the permafrost layer is thin and the bedrock is close to the surface.
The village of Newtok in the Yukon-Kuskokwim delta, which had been struggling with melting permafrost and erosion for years, finished fully relocating in 2019 to a new site on a dormant basalt volcano, where the bedrock is relatively accessible.
“So that’s something also that you may see more as the climate forces our hand,” Cooke said. “If there is a site with bedrock nearby, that may swing the decision on what looks like a safer bet for a relocation.”
In the meantime, though, residents make do shoring up what they have. In Nome, West also runs a gravel business that ships gravel fill all around Western Alaska. He said business has been doing well, especially as communities work to repair critical infrastructure like airports. “It’s a never-ending battle,” he said.
Cooke added that while the melting of permafrost certainly presented challenges to the region, he had faith that residents would find ways to deal with them.
“People have lived in this region for thousands and thousands of years. They’ve been able to adapt to changes in the environment before,” he said. “So I’m hesitant to call this a disaster. I’m fairly confident that people in the region will come up with creative solutions for it.”