When thinking about writing about our Alaskan adventure, one thing that never entered our mind was that we would be writing about the subject of permafrost. Perma-what? Those of us who live in the lower-48 don’t have to deal with the ramifications of permafrost. Before coming to Alaska, we likely heard of permafrost during a science documentary, but didn't think much about it. We certainly never had the subject come up in conversation. We don’t remember it being talked about in school. And yet, permafrost underlies about 15% of the Northern Hemisphere land mass. The permafrost area with trees is known as the Boreal Forest, and is dominated by spruce, aspen, and birch trees.
This graphic, located at "Creamers Field" in Fairbanks illustrates the Boreal Forest.
In Alaska, permafrost is a fact of life. When talking to guests coming to Alaska, it’s in the conversation perhaps several times a day. Permafrost presented challenges for the miners wanting to dig deep to the bedrock, and the pipeline design which needs a stable foundation.
The Alyeska Pipeline has passive heat conductors (evident by the tall radiator fins) that remove heat from the ground and prevent the permafrost from melting and making the ground unstable.
When glancing at a landscape, we recognize the reason for how the trees grow the way they do, or what causes the marshy conditions. The trees are short, often bent over, and they suffer from not having strong roots.
Typical tree growth in permafrost conditions. There is very little root structure.
Permafrost is a giant freezer underground of soil, rock, or sand. It is so cold that it stays frozen solid for a minimum of two years, and typically much longer. Much longer. The prefix “perma” says it all. Permafrost occurs in places nearest the arctic circle. In some places, the summer doesn’t get warm enough to thaw the ground. In the coldest regions above the arctic circle, permafrost, in areas like Siberia, can reach depths exceeding 4,500 feet (around 1,400 meters). Near the surface, the soil can be frozen just one foot below the active layer, and scientists speculate that the frozen state has been maintained for several thousand years.
The University of Alaska Fairbanks Botanical Garden studies growing food in permafrost.
In areas like Fairbanks, where we are staying, the top layer of the frozen ground can thaw some during the summer. But underneath, it’s still rock-hard frozen. The top layer that thaws and refreezes during the season changes is called the “active layer.” Fairbanks permafrost averages a depth of 150 feet (around 50 meters).
Included with frozen rocks and dirt, permafrost can also contain dead plants, animals, and other organic material that has never decomposed because it’s so cold. During times of warmer temperatures, permafrost melts and the organic material decomposes and releases gases like carbon dioxide and methane.
For those living in Alaska, permafrost obviously has an impact on life. It is a challenge for house foundations, underground water and sewers, maintaining roads, and farming. Permafrost wreaks havoc as it freezes and thaws. Try digging a well. Imagine the ground thawing, a sinkhole appearing, and your John Deere tractor being swallowed up. When it freezes, you can be driving to work and delightfully discover a huge speed bump on the highway or land a plane on a corduroy runway. Our trip to work has roller coaster sections where we dare not drink our coffee.
The constantly changing brought about by the freezing and thawing can create new bodies of water and dry up existing ones. Rivers change course and vegetation patterns are altered.
A pond surrounded by birch trees is created by permafrost conditions.
During the digging in the days of the Gold Dredges, miners found many fossils wonderfully preserved in the frozen ground. Imagine digging and finding a frozen wooly mammoth popsicle. Scientists have unearthed other species in permafrost including steppe bison, wooly rhinos, ancient camels, and ice age horses! Remains are often found to include fur and stomach contents.
Fossils discovered by the miners during the days of Gold Dredge 8. This collection is in the museum section of the dredge and includes a wooly mammoth tusk.
As we journey through the frozen land of Fairbanks, permafrost is more than just a subterranean curiosity—it’s a constant part of Arctic life. Our time in Alaska is introducing us to the wonders and challenges of living with permafrost which we previously never considered. Permafrost provides unpredictable surprises like the revealing of ice age animals and the effects on everyday infrastructure. So, while we in the lower-48 may not feel the cold touch directly, the story of permafrost is one we should all know as we contemplate the challenges endured by our Alaskan friends.
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