1379: "The Tunnel That Never Thaws"

HistoryPodcastScience
Written By JC

Interesting Things with JC #1379: "The Tunnel That Never Thaws" – Carved into ancient permafrost, this frozen tunnel holds more than ice, it holds time. From mammoth hair to volcanic ash, it’s a living archive beneath Alaska’s surface.

Curriculum - Episode Anchor

Episode Title: The Tunnel That Never Thaws
Episode Number: #1379
Host: JC
Audience: Grades 9–12, college intro, homeschool, lifelong learners
Subject Area: Earth Science, Environmental Engineering, Geology, History of Scientific Research

Lesson Overview

Students will:

  • Define the concept of permafrost and its characteristics.

  • Compare the stability of frozen vs. thawing ground in Arctic construction zones.

  • Analyze the scientific and engineering significance of the Permafrost Tunnel Research Facility.

  • Explain how permafrost preserves organic material and contributes to climate history research.

Key Vocabulary

  • Permafrost (PUR-muh-frawst) — Ground that remains completely frozen for two or more consecutive years. “In Alaska, most of the soil sits on permafrost that has remained frozen since before the last Ice Age.”

  • Syngenetic (sin-JEN-eh-tik) — Formed simultaneously with surrounding materials; “The tunnel cuts through syngenetic permafrost, locking in sediment and ice as it forms.”

  • Loess (luss) — Fine wind-deposited sediment. “The walls of the tunnel reveal windblown loess among layers of ice and volcanic ash.”

  • Ice wedge (ice-wehj) — A crack filled with ice that expands in frozen soil, creating large wedge-shaped features over time.

  • Thermokarst (THER-mo-karst) — Land surface that becomes irregular due to thawing permafrost, leading to slumping and collapse. Not directly stated in the episode but a vital concept in permafrost dynamics.

Narrative Core

  • Open – “In Alaska, the ground doesn’t just freeze in winter. It stays frozen year round.”

  • Info – The U.S. Army began studying frozen terrain in the 1960s by building a tunnel into a permafrost bluff near Fairbanks, Alaska.

  • Details – The tunnel exposes frozen layers up to 200,000 years old, containing preserved organic materials like moss, mammoth hair, and volcanic ash from ancient eruptions.

  • Reflection – The tunnel provides a critical, hands-on environment to study how climate, construction, and terrain interact in cold regions — and the risks of thawing permafrost.

  • Closing – “These are interesting things, with JC.”

Interior view of a dimly lit tunnel carved into permafrost, with arched steel supports and exposed wiring along the left wall. The ground is covered in frozen soil, and the tunnel extends deep into the distance, illuminated by warm yellow lights. Text at the bottom reads: “The Tunnel That Never Thaws – Interesting Things with JC #1379.”

Transcript

In Alaska, the ground doesn’t just freeze in winter. It stays frozen year round.

Nearly 85% of the state, around 570,000 square miles (1.48 million square kilometers), sits on permafrost. That’s soil that’s remained below freezing for thousands of years, in some places since before the last Ice Age.

In 1963, the U.S. Army began cutting into that frozen ground. Just north of Fairbanks, near a place called Fox, they carved a tunnel into a permafrost bluff. It wasn’t about mining. They were studying how to build and operate in frozen terrain.

The result was the Permafrost Tunnel Research Facility. It was created by the Cold Regions Research and Engineering Laboratory, CRREL, pronounced “crrell.” The original tunnel stretched about 110 feet (33.5 meters). Later expansions pushed it over 500 feet (152.4 meters), with a vertical shaft added to reach deeper frozen layers.

There’s no concrete reinforcement. The walls and ceiling are held in place by the cold. Inside, temperatures stay near 28 degrees Fahrenheit (–2.2 degrees Celsius), with high humidity. Heating is avoided. Lighting is limited. The tunnel must stay frozen to remain stable.

The tunnel cuts through syngenetic permafrost. That means it formed gradually, locking in sediment, ice, and organic material over thousands of years. Some layers date back 40,000 years. In deeper sections, over 200,000.

The walls reveal ice wedges, frozen river gravels, windblown loess, and buried volcanic ash. One ash layer matches an eruption from 13,000 years ago. The site has yielded preserved remains of Bison priscus, the steppe bison. Hair from woolly mammoths. Intact moss, seeds, and insect parts. These aren’t fossils. They’re still organic. Still frozen.

This isn’t a museum. Scientists use the tunnel to study how permafrost reacts to pressure, heat, or vibration. That research helped guide the design of Arctic runways, radar stations, and the Trans Alaska Pipeline. It continues to shape how foundations are built in northern Canada and Greenland.

When permafrost thaws, it doesn’t do it evenly. It slumps, buckles, and breaks apart. Roads crack. Fuel tanks tilt. Structural supports twist out of line. A 2022 study estimated more than 35 billion dollars in damage from thawing ground by the year 2050.

The tunnel helps model that risk. Its layers carry the record. Engineers and scientists study what happens not just in theory, but in actual frozen soil.

One of the early researchers was Dr. Troy Péwé (pronounced “PAY-way”). He was a geologist with the U.S. Geological Survey and taught at the University of Alaska. Péwé helped document the tunnel’s structure, tracing how its layers preserved a detailed climate record stretching back through the last glaciation.

Today, the tunnel is operated by the U.S. Army Engineer Research and Development Center. In 2015 and 2018, the site added 3D laser scanning and high resolution mapping. Researchers can now study its digital model remotely. But many still travel there. Some details can’t be seen on a screen.

There are no plaques. No narration. No guided tours.
Just frozen ground, opened up and still intact.

These are interesting things, with JC.


Student Worksheet

  1. What is permafrost, and how much of Alaska sits on it?

  2. Why was the Permafrost Tunnel created, and by whom?

  3. Name at least two types of preserved material found inside the tunnel.

  4. Why must the tunnel stay cold and unheated?

  5. How has research from the tunnel influenced engineering in Arctic regions?

Teacher Guide

Estimated Time:
45–60 minutes

Pre-Teaching Vocabulary Strategy:
Use visual aids, glossary flashcards, and real-world analogies (e.g., compare thawing permafrost to melting ice in a drink).

Anticipated Misconceptions:

  • Permafrost is not the same as ice.

  • Frozen materials in permafrost are not fossils.

  • The tunnel is not a tourist attraction or exhibit.

Discussion Prompts:

  • How do you think thawing permafrost might affect people who live in Arctic communities?

  • Why is it important to preserve and study permafrost layers?

  • What might scientists learn from the organic material preserved for thousands of years?

Differentiation Strategies:

  • ESL: Provide bilingual vocabulary lists.

  • IEP: Offer guided notes or audio supports.

  • Gifted: Challenge with research on other permafrost sites globally or 3D modeling technology in science.

Extension Activities:

  • Create a visual model showing permafrost layers and ice wedges.

  • Research the Trans Alaska Pipeline and its engineering challenges.

Cross-Curricular Connections:

  • Physics: Study the thermal properties of soil and ice.

  • History: Explore Cold War-era scientific research.

  • Environmental Science: Examine permafrost's role in climate change.

Quiz

Q1. What is syngenetic permafrost?
A. Permafrost made of concrete and steel
B. Permafrost that forms gradually with sediments
C. Artificially frozen soil for research
D. A type of volcanic rock
Answer: B

Q2. Which U.S. military branch created the Permafrost Tunnel?
A. Navy
B. Marines
C. Army
D. Air Force
Answer: C

Q3. Why is heating avoided inside the tunnel?
A. It wastes electricity
B. It attracts animals
C. It destabilizes the frozen structure
D. It makes mapping harder
Answer: C

Q4. What preserved animal hair was found in the tunnel?
A. Saber-tooth tiger
B. Modern bear
C. Woolly mammoth
D. Camel
Answer: C

Q5. What technological addition was made to the tunnel in 2015 and 2018?
A. Solar panels
B. Guided audio tours
C. 3D laser scanning
D. Air conditioning
Answer: C

Assessment

  1. How has the Permafrost Tunnel contributed to modern engineering and climate research?

  2. Describe the types of ancient evidence found in the tunnel and explain what they teach us about past environments.

3–2–1 Rubric:
3 = Accurate, complete, thoughtful
2 = Partial or missing detail
1 = Inaccurate or vague

Standards Alignment

NGSS (Next Generation Science Standards):

  • HS-ESS2-2 — Analyze geoscience data to understand how Earth’s surface has changed over time.

  • HS-ESS3-5 — Evaluate mitigation strategies for the impacts of human activity and natural phenomena on the environment.

CCSS (Common Core State Standards):

  • RST.11-12.3 — Follow a complex multistep procedure when carrying out experiments or analyzing data.

  • WHST.9-12.2 — Write informative texts that include scientific procedures and technical processes.

C3 (College, Career & Civic Life – Social Studies):

  • D2.Geo.5.9-12 — Evaluate how the physical environment influences human activity and vice versa.

ISTE (International Society for Technology in Education):

  • 1.3.Knowledge Constructor — Students critically curate resources using digital tools to deepen understanding of a topic.

UK National Curriculum (Geography – Key Stage 4):

  • Physical geography: glaciation and climate change — Understand how ice and permafrost shape the landscape and impact human activity.

IB MYP (Sciences, Criterion B & D):

  • B: Inquiring and designing — Students understand scientific inquiry by exploring Earth systems.

  • D: Reflecting on the impacts of science — Students evaluate scientific developments in societal contexts.

Show Notes

In “The Tunnel That Never Thaws,” JC explores the remarkable story of the Permafrost Tunnel Research Facility in Alaska — a one-of-a-kind subterranean lab carved into frozen Earth. Established in 1963, the tunnel offers scientists a rare, hands-on opportunity to examine syngenetic permafrost and ancient organic material dating back over 200,000 years. Its research legacy supports not only Arctic engineering but also climate science and our understanding of Ice Age ecosystems. For students and teachers, the episode connects directly to Earth science, environmental risk modeling, and history of research infrastructure. It prompts valuable classroom discussions around geology, preservation, and how past environments are key to predicting future change.

References

JC https://jimconnors.org
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