The Devastating Helene Flood Event In The Southern
Appalachians

Presentation: “The Devastating Helene Flood Event In The Southern Appalachians” by Dr. J. Ryan Thigpen and Summer J. Brown

February 3rd (Tuesday), 6 p.m., Social half-hour; please join us from 5:30-6:00 to enjoy free soft drinks and appetizers before our talk begins!

Live at the Teton County Library & Via Zoom (online)

ANNOUNCEMENT: we will soon launch a new Lifetime Membership category! Stay tuned for details…

RAFFLE AT 6PM!

The prize: a 52 million year old mass mortality plate from the world famous Green River formation from Kemmerer, WY. The plate features three complete and beautifully prepared Knightia Eocaena. This fish is an extinct, herring-like freshwater fish from the Eocene Epoch, famous for being Wyoming’s State Fossil. These small, schooling fish are preserved exceptionally well due to fine lake sediments, showing details like scales, fins, and backbone. They are found in the ancient Fossil Lake, and preserve a long-gone ecosystem. At this time Wyoming was at its current latitude; however, it was at sea level and warm. At this time there were palm trees, horses the size of collies, and crocodiles. The plate measures 8″x10″.

Raffle rules:

• Must be present to win. 
• Drawing will be at 6:00 pm in the library auditorium.
• Members receive one free ticket. One ticket per Membership.
• Additional tickets can be purchased for $5 each.
• You can buy/renew a Membership that night via cash, check, or Venmo (no IOU’s).
• Membership costs $20 individual, $35 family, and $50 for a sustaining membership.
• GJH board members are not eligible to participate.

Presentation: “The Devastating Helene Flood Event In The Southern Appalachians” by Dr. J. Ryan Thigpen and Summer J. Brown

From September 26-29, 2024, precursor storms followed by the remnants of Hurricane Helene produced >30 inches of rainfall over parts of the southern Appalachian Blue Ridge. In affected areas of North Carolina and Tennessee, many rivers greatly surpassed their historic flood-of-record levels, with some rivers like the Nolichucky and Swannanoa reaching >300 times their normal flow. The event initiated thousands of slope failures, including some of the largest and deadliest debris flows ever documented in the eastern US. Widespread and pronounced bank erosion exposed previously unrecognized paleo-flood and landslide deposits, including deposits interpreted to represent the largest magnitude flood event in the last 10,000 years, providing a unique chance to quantify recurrence intervals of past extreme events. This presentation will share on-the-ground photos, videos, and the preliminary results of ongoing surveying efforts that started five days after the flood.

The integration of ground, LIDAR, and photogrammetric analysis of the affected area will ultimately contribute to development of better mountain flood warning systems, a better understanding of conditions that trigger catastrophic debris flows, and significant insight for the Holocene record of catastrophic flooding and debris flows in the southern Appalachians.

A rescue team paddles down the Swannanoa River on Sunday, Sept. 29, 2024.

Topic: “The Devastating Helene Flood Event In The Southern Appalachians”

Time: Tuesday, February 3rd, 2026, 06:00 PM Mountain Time (US and Canada)

Join Zoom Meeting
https://us02web.zoom.us/j/4555651818?pwd=U09ObDNZOEIyZmRtMEtsdUowQnJqdz09
Meeting ID: 455 565 1818
Passcode: 576063