Uploaded October 2025 | Updated September 2026, 6 days ago
In June 1925, an entire mountainside collapsed in Teton County, Wyoming, unleashing one of the largest landslides ever recorded in North America. Known as the Gros Ventre Slide, this massive event reshaped the valley, created Slide Lake, and led to the tragic Kelly Flood just two years later.
In this episode of Wyoming Chronicle, host Steve Peck visits the Gros Ventre Slide site with Mariah Radue and Todd Stiles of the U.S. Forest Service of Bridger-Teton National Forest. Together, they explore the geologic causes, eyewitness accounts, and the remarkable ecological recovery that has unfolded over the past 100 years.
Discover how rock formations, rainfall, clay layers, and possibly even earthquakes contributed to the 1925 landslide, and how this event continues to shape modern conservation, geology education, and land management in Wyoming.
đź“Ť Topics Covered:
• The 1925 Gros Ventre Slide & its aftermath
• Formation of Slide Lake and the 1927 Kelly Flood
• Geological forces behind the collapse
• The role of the U.S. Forest Service and Bridger-Teton National Forest
• Conservation, wilderness protection, and wildlife corridors
• Lessons for modern-day landslides, including Teton Pass (2024)
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đź•’ Timestamps for Key Moments
0:00 – Introduction: The 1925 Gros Ventre Slide
0:30 – Meet the experts: Mariah Radue & Todd Stiles, U.S. Forest Service
1:40 – Comparing the 1925 slide to the 2024 Teton Pass landslide
2:50 – How 50 million cubic yards of rock moved in minutes
5:30 – What caused the landslide? Geologic and hydrologic factors
7:00 – A look at the Amsden Formation and slippery clays
10:00 – How Slide Lake formed and the Kelly Flood of 1927
13:00 – Creating the Gros Ventre Geologic Area (1960s–present)
15:00 – Ecological recovery and plant regrowth over 100 years
17:00 – Exploring rock layers: Tensleep Sandstone and Amsden Shale
19:00 – Protecting wilderness and wildlife corridors today
22:00 – Earthquakes, predictions, and “Uncle Billy” Bierer’s warning
24:00 – Lessons learned: Could it happen again?
26:00 – The enduring story of geology, conservation, and resilience
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#GrosVentreSlide #WyomingPBS #WyomingChronicle #WyomingHistory #Geology #Landslide #NaturalDisasters #TetonCounty #SlideLake #KellyFlood #BridgerTetonNationalForest #USForestService #EarthScience #GeologicHistory #WildAndScenicRivers #PublicLands #WyomingNature #PBSDocumentary
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With Wyoming PBS content you can delve into Wyoming history, explore the breathtaking beauty of our iconic national parks, and immerse yourself in the inspiring tales of Native American leaders, ranching life, the wonders of nature, and the many things to do in Wyoming. Whether you're seeking inspiring narratives or planning your next adventure in our beautiful state, WY PBS is your trusted guide.
Subscribe to our channel: youtube.com/wyomingpbs
Subscribe to our email newsletter: wyomingpbs.org/newsletter-signup-form
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In June 1925, an entire mountainside collapsed in Teton County, Wyoming, unleashing one of the largest landslides ever recorded in North America. Known as the Gros Ventre Slide, this massive event reshaped the valley, created Slide Lake, and led to the tragic Kelly Flood just two years later.
In this episode of Wyoming Chronicle, host Steve Peck visits the Gros Ventre Slide site with Mariah Radue and Todd Stiles of the U.S. Forest Service of Bridger-Teton National Forest. Together, they explore the geologic causes, eyewitness accounts, and the remarkable ecological recovery that has unfolded over the past 100 years.
Discover how rock formations, rainfall, clay layers, and possibly even earthquakes contributed to the 1925 landslide, and how this event continues to shape modern conservation, geology education, and land management in Wyoming.
đź“Ť Topics Covered:
• The 1925 Gros Ventre Slide & its aftermath
• Formation of Slide Lake and the 1927 Kelly Flood
• Geological forces behind the collapse
• The role of the U.S. Forest Service and Bridger-Teton National Forest
• Conservation, wilderness protection, and wildlife corridors
• Lessons for modern-day landslides, including Teton Pass (2024)
---
đź•’ Timestamps for Key Moments
0:00 – Introduction: The 1925 Gros Ventre Slide
0:30 – Meet the experts: Mariah Radue & Todd Stiles, U.S. Forest Service
1:40 – Comparing the 1925 slide to the 2024 Teton Pass landslide
2:50 – How 50 million cubic yards of rock moved in minutes
5:30 – What caused the landslide? Geologic and hydrologic factors
7:00 – A look at the Amsden Formation and slippery clays
10:00 – How Slide Lake formed and the Kelly Flood of 1927
13:00 – Creating the Gros Ventre Geologic Area (1960s–present)
15:00 – Ecological recovery and plant regrowth over 100 years
17:00 – Exploring rock layers: Tensleep Sandstone and Amsden Shale
19:00 – Protecting wilderness and wildlife corridors today
22:00 – Earthquakes, predictions, and “Uncle Billy” Bierer’s warning
24:00 – Lessons learned: Could it happen again?
26:00 – The enduring story of geology, conservation, and resilience
---
#GrosVentreSlide #WyomingPBS #WyomingChronicle #WyomingHistory #Geology #Landslide #NaturalDisasters #TetonCounty #SlideLake #KellyFlood #BridgerTetonNationalForest #USForestService #EarthScience #GeologicHistory #WildAndScenicRivers #PublicLands #WyomingNature #PBSDocumentary
---
With Wyoming PBS content you can delve into Wyoming history, explore the breathtaking beauty of our iconic national parks, and immerse yourself in the inspiring tales of Native American leaders, ranching life, the wonders of nature, and the many things to do in Wyoming. Whether you're seeking inspiring narratives or planning your next adventure in our beautiful state, WY PBS is your trusted guide.
Subscribe to our channel: youtube.com/wyomingpbs
Subscribe to our email newsletter: wyomingpbs.org/newsletter-signup-form
Follow us on Facebook: facebook.com/WyomingPBS
Follow us on LinkedIn: linkedin.com/company/wyoming-pbs
