Because of the unique temperature, weather, and location of Fairbanks, a great deal of research takes place around the city. One of the most well-known research projects in Fairbanks is U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel Research Facility. The tunnel was excavated in the 1960s in order to study a variety of scientific questions related to permafrost. The tunnel is generally not open to the public, so when we got the opportunity to take a tour with a group of students visiting the University of Alaska, we jumped at the chance.
Permafrost is soil that remains frozen continuously, despite above ground temperature. Permafrost does not mean that the ground is frozen permanently; the term may refer to ground that remains below freezing from anywhere between two to thousands of years. Permafrost exists in different amounts throughout Alaska (here is a fairly recent map of permafrost distributions). Parts of southern Alaska have areas with little to no permafrost, while northern Alaska is characterized by continuous permafrost due to its cold temperatures year-round. In much of the interior of Alaska, the permafrost is defined as discontinuous, meaning that it occurs in patches throughout the land. Discontinuous permafrost is a particularly large headache in Alaska because of the problems it can cause for construction.
We noticed several of the problems discontinuous permafrost can cause while we were travelling to Fairbanks from the Lower 48. Once we entered the Yukon Territory, Canada and until we reached Fairbanks, the road was rough. Cracks, potholes, and frost heaves populated many stretches of road, and sometimes the road was so bumpy that we had to slow down and cross into the other lane in order to navigate it safely. These inconsistencies in the road are caused by periodic freezing and thawing throughout the years. Along the Alaska Highway, we saw two research projects (one still in progress and the other long abandoned) investigating methods to regulate the temperature of the ground underneath the road. Another issue caused by frequent freeze-and-thaw cycles was evident when we saw the crooked utility poles that paralleled the road in Alaska. Most utility poles were leaning to some degree, and some of the poles we saw looked seconds away from collapsing. Although many poles were leaning haphazardly in different directions, the electrical wires between them were in no danger of being stretched. Engineers and utility workers in this state must factor this phenomenon into their plans.
In Fairbanks, we learned that permafrost is an important factor to consider when buying a home or a housing lot. Buying or building a home on permafrost requires extra considerations to ensure stability and prevent heat losses to the ground. Additionally, there is always the chance that the permafrost may thaw, which can cause a home’s stability and structure to be compromised. Research by scientists at the University of Alaska indicates that, as Alaska’s surface temperature warms, areas of permafrost in the Fairbanks area will vanish within this century. As that happens, many homes built on permafrost may begin to sink unevenly into the ground. This link to an old but accurate article about the permafrost in Fairbanks by our local paper, The Daily News-Miner, summarizes the risk of disappearing permafrost for those who are interested.
With all of these issues in mind, we were excited to visit the permafrost tunnel and learn how scientists use this handy site. The tunnel is about a twenty minute drive from Fairbanks. On the outside, the research area is underwhelming; if you missed the sign indicating the tunnel, you might think the site is someone’s work area. Two tiny buildings, an office and a visitor center, stand outside the tunnel’s entrance. In the visitor center, research posters outlined some of the things the tunnel has been used for in the past. Old photos showing the excavation of the tunnel and informational posters on Alaska’s permafrost were posted throughout the room. Perhaps the most interesting, though was the collection of bones that were found while creating the permafrost tunnel. Bones from mammoths and an extinct type of bison were found while excavating the tunnel, and some of these are on display in the center.
Going into the tunnel was a strange experience. Although it was 65°F and sunny outside, we bundled up in warm coats, gloves, and hats. The entrance to the tunnel is built right into the side of a hill, and crossing the threshold feels like walking into a Hobbit House. After the first door, there is a small entrance space and another, more official-looking door. As we crossed into the entrance space, the air was notably colder than the warm air outdoors. The second door looked like the entrance to a walk-in freezer. As we stepped through the second door, the air became even colder. Because summer temperatures are too warm for the tunnel to remain frozen and stable, the tunnel is mechanically cooled to a temperature of 25°F during summer months. We shivered with the change of temperature and made our way slowly down a slightly frozen ramp to explore the tunnel.
In the tunnel, our guide pointed out many interesting features about the geology. Some of the most interesting features to see were visible ice wedges. An ice wedge is a portion of ice that forms and creates a crack in the ground. It was quite interesting to see the transition between solid ground and frozen ice wedges. One fascinating feature dealt with the vegetation in the tunnel. The earthen roof of the tunnel is covered in tiny roots that extend downward from the ceiling. These roots are from plants that existed more than 30,000 years ago and were covered in soil and frozen in the ground. Research on the types of plant roots found when excavating the tunnel has revealed what type of vegetation was thriving thousands of years ago. An unexpected but prominent feature of the tunnel was the distinct, slightly unpleasant smell. The earthy, musty smell is unlike anything we’ve experienced before.
After about an hour of exploring the tunnel, we made our way back to the warm outdoors with a new-found appreciation for the researchers studying permafrost. It was incredible to experience such an interesting research site and learn about some of the scientific studies being conducted around Fairbanks. Though the tunnel is not usually open to the public, there are occasionally exceptions. If you ever get the chance to visit this special research site, we suggest you take it!
Leigh joins me in writing about our adventures living in Alaska.