CRREL Permafrost Tunnel – Fairbanks, Alaska
By: Courtney Dowd-Stanley
Alaska’s frozen underground permafrost tunnel is quite the sight to see. The tunnel runs through permafrost, a natural frozen phenomenon hiding under the surface of the ground, and brings it into plain sight.
So, what is permafrost? Permafrost is permanently frozen ground made up of soil, rocks, or sediment. Technically, in order to be classified as permafrost, ground must be at a temperature of 32 degrees F (0 degrees C) or less for more than two years. Structurally, permafrost is incredibly important as its melting can cause erosion, landslides, and a variety of ground subsidence issues. It may come as a surprise to some, but permafrost can be found beneath nearly 85 percent of Alaska’s ground surface. It is, however, thickest in the arctic regions of the Last Frontier, north of the Brooks Range.
With permafrost being such a prevalent part of Alaska’s landscape, it makes sense that there would be a facility that allows researchers to study it up close. The United States Army maintains and operates the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel Research Facility located 16 miles north of Fairbanks in Fox, Alaska. CRREL is a part of the U.S. Army Corps of Engineers Engineer Research and Development Center. As the tunnel serves as an active underground laboratory it is not open to the public, but a virtual tour is available through the CRREL website HERE. We’ve also included a YouTube video touring the facility below.
The tunnel is carved into the side of a molehill and is reported to be roughly 50 feet underground and 360 feet in length. It was built between 1963-1969 in order to study underground excavation methods in permafrost, but it was soon realized that the tunnel would be a great place to study natural sciences such as geology and paleontology along with a variety of mining and construction methods in frozen environments.
The frozen environment inside the tunnel is over 40,000 years old and is filled with fascinating soil, rock, and paleontology features. As you navigate through the tunnel via the virtual reality tour, you’ll notice ice-crusted roots hanging from the ceiling.
Many of the ice wedges formed inside the tunnel turn distinctive shades of amber colors when trapped air bubbles combined with sediment mix together in such small, confined spaces.
While the specific area was once thought to be the underside of an ancient lake, more recent studies have shown that it might actually just be another filling of cracks with water turned to ice.
Inside, a truss system keeps the tunnel safe and secure from collapsing. A refrigeration system with flexible ductwork placed throughout the tunnel is used to assure that the ground stays frozen during Fairbanks’ notoriously hot summer months. The system also helps blow cold outside air through the tunnel in the winter. There are also extensive walkways to keep visitors from walking on the slippery silt underneath the metal paths.
Whether you are a lucky researcher who gets the opportunity to study this unique permafrost tunnel up close and personal, or you are just an interested bystander (like us) taking the online virtual tour, this unique attraction is a must-see. You’ll have the chance to learn about ice wedges, ice lenses, and other permafrost features including the discovery of bones from the Pleistocene of bison, mammoth, and horse.
Check out the incredibly interesting YouTube video below to experience a glimpse inside this unique permafrost tunnel in Fairbanks.
Looking for more where that came from? You’ll love learning about El Capitan Cave, Alaska’s largest aboveground cave that will give you an enchanting middle-earth type of experience. Check out Matanuska Glacier: Visiting One Of Alaska’s Most Amazing And Easily Accessible Places. You might also enjoy reading about the isolated places in Alaska where you can actually view Russia from your doorstep. This historic read on Portage – The Sunken Alaska Ghost Town That Nature Is Reclaiming is also quite interesting.