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Permafrost Tunnel Gateway Tour

Explore an Arctic research facility first excavated in the 1960s, including features such as ice wedges as tall as houses, green grass from thousands of years ago, and bison bones embedded in permafrost. Some features are up to 40,000 years old! Learn about current research and rapid changes happening to permafrost. Be one of the first to experience this guided virtual reality tour of a facility seldom open to the public.

This virtual tour features Tom Douglas and Robyn Barbato with the U.S. Army Corps of Engineers, Patrick Druckenmiller and Jennifer Moss with the University of Alaska Fairbanks, Mike Brubaker with the LEO Network, and Anna Liljedahl with the Woodwell Climate Research Center. The program is moderated by Jason Cervenec with the Byrd Polar and Climate Research Center with help from Joseph Helterbrand, Karina Peggau, Amadou Agne, and Addie White.

Questions we DID NOT have a chance to answer during the live event but have answered here. The "find" feature in your web browser can be used to look for keywords of interest.

Individuals replying to questions:

  • JMC: Jason Cervenec
  • AKL: Anna Liljedahl
  • TAD: Tom Douglas 
  • PSD: Patrick Druckenmiller
  • RB: Robyn Barbato

What soil is this? Turbels?

TAD: We would call it cryotic ground or permafrost soil in a broad sense. There are turbels nearby but the majority of the soils are ice cemented silt and gravel.

What kind of climate control is at work in Blue Babe's display case?

PSD: Not really anything special. Mummy has been treated so it's stable.

Why are the horns so different compared to the last picture? different species?

PSD: Horns vary a bit by sex (males bigger, bit longer) and age of individual. And there are different species of bison so that may explain if you see different drawings…

How do you ensure that Blue Babe doesn't deteriorate when being displayed?

PSD: Blue Babe has been treated using taxidermy methods so it is stable.

How did the mammoth evolve into the elephant?

PSD: Mammoths didn’t actually evolve into modern elephants - but they share a recent common ancestor (now extinct).

How do you know what the Woolly Mammoth looked like?

PSD: We have mummified mammoths! And cave paintings in Europe that show what they looked like too!

How is Blue Babe preserved once outside of the permafrost?

PSD: Blue Babe has been treated using taxidermy methods so it is stable.

Is Blue Babe stored in cold to keep it preserved?

PSD: Nope. No cold needed.

Are there any good books or journals to keep an eye on for those who are interested in keeping up with Ice Age/Arctic studies?

PSD: There are a lot of technical journals that most specialists use. For the general public, some of these get “processed” for sharing by some news outlets like Science News. I’ll let others suggest some ideas of other outlets.

AKL: The Arctic Institute offers a weekly newsletter (over email) that covers mostly law and politics but also science and the environment: https://www.thearcticinstitute.org/

JMC: For teachers and other educators, there is a group called Polar Educators International. This group has an active social media presence and shares a lot of current research in formats understandable to non-researchers. Their website is at https://polareducator.org/

Have you studied the effects of "big chillers" on the outside temperature of tunnel?

TAD: Do you mean are our chillers causing ground near the Tunnel to be frozen that otherwise would not? We find the chillers maintain slightly below normal ambient temperatures (based on a given depth) to about a meter into the wall and that is about it. We are planning to install some thermisiphons so “super cool” some soils above the main Tunnel entrances.

What if there is a bacteria or something which might cause humans to be ill? Are some potentially harmful to humans when thawed?

TAD: This is a good Robyn question! My answer is that indigenous people have been living on and near and in some cases inside permafrost for thousands of years. No harmful bacteria have been identified. But there are people doing large surveys to make sure.

RB: Most bacteria are beneficial, but some can be harmful. Researchers have found harmful bacteria in permafrost, just as others have found harmful bacteria in temperate, tropical, and desert soils. However, very specific conditions must be met for the bacteria to infect a plant or an animal. And as Tom noted, humans interact with soils and permafrost often.  It is unlikely to get sick unless certain conditions are met, but researchers are surveying permafrost, especially since it is rapidly warming due to climate change.

How big are the pores in the soil compared to the pores in the permafrost?

TAD: I am not totally sure I get this question. The soils are ice cemented so there is little open pore space at all.

How many different kinds of bacteria did you find in the tunnel? (asked by a 4th grader)

RB: On average, we find about two million bacteria in each sample we’ve collected in the tunnel, represented through 20 classes of bacteria! For context, humans are in the class: Mammalia, genus: Homo, and species: sapiens

What kind of virus do you see the most?

RB: To my knowledge, no one has published on specific viruses found in the tunnel. What a wonderful idea for a new research project! Maybe you will be the first to discover this! In permafrost-affected soils in northern Sweden, a research group found Tectivirus, Inovirus, among others. Another group found Nucleocytoviricota in ancient Siberian permafrost.

What was the oldest organization about climate change?

TAD: From Google: “The Intergovernmental Panel on Climate Change (IPCC) was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988. The establishment of the IPCC was endorsed by UN General Assembly in 1988.”

Why not use the excess of Shipping Containers available for Arctic Housing? They can be pier mounted, and moved easily if needed.

TAD: Shipping containers are used quite a bit for storage and of course shipping. One challenge for housing is when it is extremely cold outside yet warm and humid inside you need walls that can “breathe” a bit and this means lots of air circulation and various other engineered solutions. You also need a thick insulation. There are many prefabricated structures that work for this but shipping containers without a lot of modification would not be suitable human habitat (housing). 

JMC: Here is an article discussing the balance between maintaining heat and providing sufficient ventilation that also mentions ongoing research and traditional building designs: https://nunatsiaq.com/stories/article/how-better-design-can-make-rural-alaska-homes-healthier/  

MB: The idea of using shipping containers is a good one. I makes use of a valuable and practical container that is needed to ship the supplies in.  Along with frequent use as sheds, I have seen examples of both single family homes and multi-family homes in Alaska. There is a multi-family home in Kotzebue I was particularly impressed with. There are also innovative projects at UAF to use shipping containers for home construction. See: https://www.akbizmag.com/industry/architecture/uaf-students-design-shipping-container-house/

Additional questions we answered during the live event with typed responses. The "find" feature in your web browser can be used to look for keywords of interest.

  1. I live in Alaska, is there ever an opportunity for the public to tour the permafrost tunnel?

The tunnel was only open once to the public in the last decade or so.

  1. Why was it built?

The Permafrost Tunnel was excavated originally in 1963–1969 for the study of permafrost, geology, ice science, and mining and construction techniques specific to permafrost environments.

  1. I thought there would be snow in Alaska right now?

Yes, we filmed last summer.

  1. This might seem tangentially related, but to my understanding there is an army equipment testing center in the Fairbanks area. Have you or your research been used in any cold weather equipment trials?

Yes. That is the Cold Regions Test Center (CRTS) at Fort Greely, Alaska.

  1. How deep is it?

The old tunnel section is approximately 110 meters in length, 2 to 2.5 meters high, 4 to 5 meters wide, and 15 meters below the surface. The new tunnel section is longer and wider and taller!

  1. What is the temperature inside?

Just a few degrees below freezing, so -3 to -5C or so. It needs to be a few degrees below freezing as at "warmer" freezing temperatures the ice actually becomes a bit plastic and the tunnel wall collapses. That is partly artificially cooled because the ground (permafrost) around the tunnel is -1C.

  1. When was this tour done? Didn't see any snow on the ground outside and we still have several feet of snow

We filmed/took photos last summer. There is snow right now outside the tunnel.

  1. How has global warming affected the tunnel?

We have warmed about 3C since the 1970s and our mean annual temperature is now close to 0C. We have to run chillers in the summer, and we have a lot of locations above the tunnel that are actively thawing.

  1. Greetings from Ukraine! What are the oldest ice wedges you have in the tunnel?

About 24,000 years old.

  1. Very cool. Are the grass species present there still in existence today?

Slightly different species now. It is much warmer.

  1. Is the grass still living? Is it frozen?

Its frozen, been frozen for thousands of years, so it is not growing anymore.

  1. How do you know that dust deposition is 1 mm/yr.

Researchers have dated volcanic ash layers that are buried in the silt and then measured the thickness of silt above it.

  1. Any microbes you found with these upside-down "grasses" that were also previously frozen?

They are probably there.  Something for all of the new emerging scientists to study!

  1. What was the original inspiration for digging the tunnel?

Engineers originally used the tunnel to evaluate underground excavation techniques in permafrost.

  1. Have you ever found crystals in the permafrost?

Ice crystals. Some small rock fragments, too.

  1. What if someone melts some of the ice and a chain reaction happens, or will the water freeze as it's dripping down?

The chain reaction is not something we worry about. We do have to plan for where the lights are, how well insulated the door is, etc.

  1. Who thought of the idea to build the tunnel?

The Army Corps of Engineers. They wanted to learn about excavating in permafrost and whether equipment could be stored inside the Tunnel.

  1. What's the oldest sample of permafrost you have found?

In the tunnel we go back to 42,000 years old. But in other places it is up to a million years old.

  1. Is the wood petrified?

Technically, no. It has just been frozen quickly enough. It never rotted.

  1. How is there wood in the tunnels? did there use to be trees in the tunnels?

Where you find wood or grass in the tunnel is where the ground surface used to be several thousands of years ago and then that old surface got buried by silt that blew in with the wind from the glacier-fed riverbeds or because of erosion (soil slumping in and covering the vegetation).

  1. How does the ventilation system work in the tunnel? Would the heat generated affect maintenance of the tunnel?

We have large fans and pipes along the roof to move air. WE do have to make sure we track heat sources like motors and lights.

  1. How does it freeze quickly if deposition rates are 1mm (about 0.04 in) per year? Would it not thaw each summer?

I think the grass that you see were buried by a small "landslides" or local erosion events that could have been triggered by an unusually warm summer that caused the permafrost to thaw (and then the permafrost came back)

  1. Did this tunnel come from glacial ice or mountain ice?

Neither. It formed from the slow and steady deposition of silt and organic matter during cold periods.

  1. How deep is the permafrost there until mother bedrock material is reached?

Bedrock can be permafrost. Thickness in the Fairbanks area is up to about 100 feet. In northern Alaska it is up to 1,000 feet thick!

  1. Do you know what caused this rapid death/mummification?

You can have abrupt permafrost thaw events caused by unusually warm summer or heavy rains and that can result in the formations of depressions that fill up with water and if anything falls into that pit, they will be immediately buried in mud and water. With permafrost continuing to thaw and the pit expanding horizontally, then more soil covers the tree/animal and that soil acts as a blanket so the permafrost can reform before the animal/plant has had time to degrade.

  1. Were any human remains found?

No. Humans are believed to have come through about 10,000 years ago and our "youngest" permafrost in the tunnel is 18,000 years old.

  1. Why would the lion kill it and not eat it?

Perhaps it was teaching it's young to hunt or was scared off by another animal.

  1. Is it possible for a virus to live in the permafrost? there are some that were found living in the ice of Antartica

Definitely possible. Robyn can speak to this. But the viruses may not necessarily be harmful.

  1. Is there any risk of releasing frozen viable now-extinct pathogenic microorganisms while digging/disturbing the permafrost?

We are actively studying this.  To put it into context, Bacillus anthracis (causes anthrax) is a common soil bacterium that is commonly found in soil.  It is under particular circumstances that it harms animals.

  1. If teaching its young to hunt, they would have eaten it. If scared off by a larger animal, the already killed animal would have been an easy meal for the lion's predator. Perhaps something catastrophic occurred rapidly and caused it to be preserved in its current form, like a flood.

Yeah! Maybe the little guy got attacked, ran away and fell into a mud pit. Those mud pits form today too when permafrost thaws because of really heavy rains or really warms summers. I have seen dead moose fallen into these "permafrost thaw mud pits".

  1. Thanks, a follow up is: is 1mm/yr. falling on the average today or was the 1 mm/yr. for a past period?

The deposition rate is actually higher during periods where we have a lot of vegetation (large surface area for the dust to settle on) than during times when the glacier coverage was large. I believe the 1mm rate is the current rate.

  1. Can the same things (fossils of animals) be found in mountain permafrost?


  1. The 1mm/year question above about the freeze rate was a good one, because yes, wouldn't that have thawed in the summer of that year to prevent that build up?

Agreed. More likely is that these animals/grasses were covered by a local erosion event. For example, we can have these pits filled with mud and water form as permafrost thaw and the bottom of that pit gets filled in as the walls of the pit collapses.

  1. Wouldn't the wedges move when the continental crust moves?


  1. What is the maximal size of ice wedges? What is the average distance between them?

The ice wedges are relatively shallow (10 to 100ft) compared to the continental crust.

  1. What tunnelling method was used to advance the tunnel into the permafrost?

The machine used is referred to as a 'road header'. It is commonly used to advance tunnels through soft rock-type ground conditions, such as permafrost would be.

  1. What’s your thoughts about carbon and methane emissions in mountain permafrost regions (European Alps and Himalayas) other than Arctics?

Carbon dioxide, methane, and nitrous oxide are being measured in high latitude and altitude regions.  Because they are greenhouse gases, scientists are estimating the sources and sinks of these gases.

  1. Has the temperature of the tunnel changed over time since it is open to the outside, people and lights give off heat?

The temperature of the tunnel would for sure have changed over time (because of bringing in warm summer air from the outside etc.) if it hadn't been for the big cooling fans that are running all the time.

  1. Is there any mold?

We found fungi in the tunnel!

  1. When do you decide to call the ice permafrost?

Permafrost is ground that remains completely frozen for at least two years straight.

  1. Have you studied the effects of "big chillers" on the outside temperature of tunnel?

Yes.  We use active cooling through thermosiphons (solar powered) to help keep the ground frozen in summer.

  1. How has the tunnel stayed constant & survived all this time, without artificial cooling? Global warming?

Big cooling fans keep the tunnel at -4C. Without them, the tunnel would collapse because of the warming air temperatures and because of any warm air that would sneak in when people enter the tunnel in summer.

  1. What education does it take to become this type of scientist?

You definitely need an undergraduate degree in science or engineering. If you want to lead your own research projects, then you usually need a PhD too, but not always.

  1. What is the Boreal Forest?

It is the forest in the northern parts of the northern hemisphere that has pine and spruce trees.

  1. How many entry points does the tunnel have?

The tunnel has two main entry points.

  1. Have you ever found dinosaur bones in the tunnel?


  1. Pingos?

Yes, there are some pingos near Fairbanks!

  1. Which village is it?

Point Lay, Alaska.

  1. Do inhabitants receive help from the state to relocate after permafrost thawing underneath their houses?

Not even close to the help that people really need. There is no insurance for a homeowner that deals with permafrost thaw.

  1. is melting of ice wedge the cause of the deterioration of the road into the back area of Denali National Park?

The Denali Park Road that is affected by the landslide is due to thawing of permafrost in general and ice wedges are not present at those steep mountain sides. We do have lots of problems with melting of the top of ice wedges on roads in Alaska though! It results in big roller coaster bumps, almost like riding big waves.

  1. How do you estimate the below ground ice wedge (volume, thaw, etc.) from aerial imagery? How accurate are the estimations?

You combine field measurements of the ice wedge volume (that are done by doing many coring holes) and remote sensing studies of the ice-wedge polygon diameter and trough-width. Ultimately you need overlap between the two at each region that has different soils/glacial history, so you need collaborations between many scientists in many countries to do this estimate well. The accuracy of this way to estimate permafrost ice volume is much better than any estimates across large regions to date, but the science community sure has work to do in figuring out the accuracy of this combined approach.

  1. how deep is the active layer

The active layer around Fairbanks is about 50 cm (or two feet) in the spruce forest.

  1. How deep do the roots go? are they limited to the soil that thaws in the summer only?

Generally limited to seasonally thawed soil.

  1. How much does the thawing of permafrost and melting of ice wedges affect the results of earthquakes that may happen in the region?

Not at all.

  1. How long will the Permafrost Tunnel last (in years)?

Hopefully forever!

  1. What is the stratigraphy of ice-wedge structures? How many horizons with ice wedges do you have in the tunnel and what age?

Ther are two main ice wedge forming events/times.

  1. the earth is losing its orbit and going into the sun is another cause of global warming


  1. Why do they dig holes in the tunnel??

Core sample collecting!

  1. Are the bacteria and microorganisms you found alive?

It’s alive!

  1. How were you able to count the microorganisms?

We separate the microorganisms (mainly bacteria) from the soil and stain them.  Then we look at them under the microscope and count them.

  1. What is the grossest thing you’ve found in the tunnel?

Nothing gross!

  1. What things did you find in the tunnel? (Asked by a 4th grade student)

Bones, ice, silt, grass, rocks, microbes, ice, you name it!

  1. Have you discovered a new microorganism?

We have a repository of microorganisms from the tunnel that we’re studying further.  We might discover a new one!

  1. How did you find the tunnel? (Asked by a 4th grader)

There was a perfect location near Fairbanks, Alaska.

  1. Will the permafrost ever melt? (4th grade question)

The top of the permafrost is thawing at many places across the Arctic. But permafrost can also form again if a lot of mosses start growing on the ground surface, for example. Mosses are like a great blanket, keeping the cold in the ground protected from the warm air.

  1. If I visit the tunnel in person, can I get a dose of Dr. Barbato's enthusiasm? Love it.

Absolutely!  I love the work I do!  Thank you for your kind words.

  1. Is there a signature bacterium native to AK, say versus Maine or other locations?

There is an element of biogeography to soil bacteria, as there are certain combinations more likely found in cold regions soils as opposed to deserts.

  1. Are the grasses and plants found in the tunnel extinct as well and have you found seeds that you can grow?

My colleague, Nancy Parker, looked at the ancient pollen in the tunnel to see relics of plants that used to be there.  So far, I don’t think anyone has found seeds that can grow.

  1. Do the bacteria make you sick? (4th grade question)

Great question!  Most don’t.

  1. Is it possible to tour the tunnel in person?

The tunnel is closed to the public. If you are a researcher, you can get access to do your research in the tunnel.

  1. What kind of work do you like to do?

Visiting interesting places and meeting people. And working with them to try to help the world be better.

  1. Is there bedrock in the tunnel, and if not, how much loess is below the tunnel?

The silt is about 50ft thick, then there is about 10ft of gravel, and the bottom is really "crappy" bedrock in the form of schist.

  1. Have released microbes, due to thawing, hurt people or animals, currently?

A few years ago, in Siberia, thawing permafrost exposed a caribou that died from anthrax (Bacillus anthracis spores).  When it was re-exposed, other caribou died.

  1. How do you know where to build the new infrastructures? How long is the tunnel?

Good question.  We test the ground and use climate projections / models.

  1. Where else in the world does permafrost exist?

Permafrost can be found under about 25% of the northern hemisphere land. Other places are on top of Hawaii's tallest volcanoes and Antarctica of course!

  1. What are the dates of the bottom silt and the gravel?

42,500 years old!

  1. How is permafrost possible in a volcano in Hawaii? That's awesome

More "on" than "in." If the mean annual air temperature is cold enough permafrost can be created and maintained.

  1. Why not use the excess of Shipping Containers available for Arctic Housing? They can be pier mounted and moved easily if needed.

Great idea. I have seen this done for single family and multifamily homes in Kotzebue.