FAIRBANKS, Alaska – Soils in Alaska’s second-largest city are marred by discontinuous permafrost. They’re unpredictable and dynamic and they shift and change, sometimes dramatically from season to season.
“When I was a kid I used to ask … ‘when’s the permafrost going to all be melted, so we can have decent roads?’” joked Tim Henry. He grew up in Fairbanks. Now 31, Henry owns an engineering firm and specializes in structural design work. The response he got as a kid? “They’d say, ‘Tim, in your lifetime, the permafrost will never be thawed,’ and that was kind of the thought.”
Together, we went on a small tour of the Golden Heart City late last October. Our first stop was at an old but popular gas station on the Steese Highway, where a retaining wall has a large vertical crack. The roof is sagging and the ground at the base of the building bows in a great U-shaped depression. The permafrost-laden soil below isn’t as ice-rich as it was when this building went up more than two decades ago.
“There’s a lot of bad things happening with soils,” said Henry. “I mean, compared to just four or five years ago, there’s a lot more [problems]. Seeing the properties that have been there for a long time and then move after 20 years, that’s … real scary, because no one is expecting it,” he said.
Our second stop brings us to a house in a low-lying wetland along a narrow dirt road north of the city center. Soils here drain poorly in summer and temperatures are absolutely frigid in winter. The constant freeze-thaw can wreak havoc on building foundations.
This house is quaint and brown, with cedar siding and a small deck off to one side. According to Henry, it has been here for about 25 years, but there is something terribly wrong.
“It’s my understanding that at some point in the middle of winter, water [came] up into the basement,” he said. The entire house looks like it was built in the middle of an ice rink.
“That’s a very interesting aspect of permafrost degradation,” said Ronald Daanen, a geohydrologist with the Alaska Department of Natural Resources. Groundwater that exists under permafrost can become pressurized, he explained.
“If you build a house on it the wrong way, and you affect the permafrost, suddenly you can get all this water released right underneath your house.”
Daanen said it’s nothing new. “There are plenty of anecdotes about old cabins being filled with ice because of that,” he said. But in this case the monetary losses are huge. There’s the homeowner, the mortgage lender and also tax revenue that would have otherwise gone to the Fairbanks North Star Borough.
This scenario is playing out more frequently in Alaska’s interior. Lately, the springtime has brought with it extreme amounts of rain. In 2014, the inundation made headlines when the ground in places literally gave way. In the last three years, sinkholes have been reported in neighborhoods, at a local golf course and even on the University of Alaska, Fairbanks campus.
At least one of those holes is likely an abandoned mine shaft – a remnant from a gold rush that came up the Chena River valley a century ago. Others are reminders of a more ancient time. Scientists believe landscape alterations and changing drainage patterns are causing giant ice wedges to melt.
“People typically think of a land surface as stable,” said Daanen. But where there’s permafrost, he said, the ground is anything but stable. “It’s just always in motion,” he said, but “that motion is not measured in minutes, it’s measured in decades.”
Daanen said he and colleagues can’t say for sure if excessive rain in warmer seasons means landowners should expect to see their front yards or even their houses shift with the ground.
“What most people do agree upon is that the weather is going to be more erratic, so we will be having more extremes – more extreme wind, more extreme rainfall,” he said. In the long term, Daanen expects the landscape will change accordingly.
Wes Madden has been selling real estate across Alaska for a decade. “Pricing wise, to keep it reasonable, for a lot of people, they have to be on that type of soil,” he said. Many contractors build homes on adjustable foundations or steel pilings, but even that isn’t foolproof.
He said he’s seen the biggest effects to septic systems. Madden adds that it’s unusual for insurance policies to address problems that arise because of changing permafrost dynamics. And, he said, there’s no one keeping track of the financial cost when it comes to the impact on commercial and residential property.
“By and large, I don’t feel like it impacts the real estate market enough to have an overall effect.” he said. “It’s the environment. You can’t control what earth is going to do and there are surprises on every property.”
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