Grand Teton Rangers Warn: Spontaneous Rockfalls Reshape Peaks — Climbers Urged to Avoid East Ridge

Rangers Warn Visitors to "Look Up": Spontaneous Rockfalls Reshape Grand Teton Peaks

Grand Teton National Park, in Jackson Hole, Wyoming, is renowned for its jagged granite summits and abundant wildlife. Since early July 2025, park rangers say a series of spontaneous rockfall events have altered parts of the Teton skyline and created new hazards for climbers and backcountry users.

The most prominent incident occurred over the Fourth of July weekend, when a large section of a secondary summit on the Grand Teton — the feature known as the Second Tower — broke away. The park's Jenny Lake Rangers posted on Instagram:

"Heads Up! Multiple major spontaneous rockfall events have occurred,"

noting that portions of the Second Tower and a large boulder fell onto the winter route to the Lower Saddle. Rangers also reported a visible debris field on the Teepe Glacier after around 48 hours of intermittent events. Climbers who traditionally used the East Ridge route have been the most directly affected.

Why this is happening

Geologists, including John Willott who spoke with local outlets, say the Tetons are relatively young mountains geologically and still display "growing pains" from their formation. Composed mainly of granite, the peaks developed fissures and fractures as the rock cooled and the range was uplifted. Those long-standing weaknesses are susceptible to weathering.

Rangers and scientists identify repeated freeze–thaw cycles as a primary trigger: water and snow entering cracks freeze, expand, and widen fractures; when they thaw, support is lost and the process repeats until rock detaches. Other factors such as seismic activity, root growth, and increasingly warmer temperatures that reduce persistent snow and ice can accelerate collapse.

"If you think about the Appalachians back east, they were as tall as the Himalayas 350 million years ago. Now they are bumps in the road,"

Willott adds that mountain ranges naturally degrade over long periods and that warming conditions can increase the frequency of rockfall events by exposing rock faces formerly held together by ice and perennial snow.

Recent history and trends

This is not an isolated event. In 2022, other large sections of the Second Tower also collapsed and sent rock onto the East Ridge trail. Park staff and climbing guides warn that these failures are part of an ongoing process: both large and small rockfalls can occur in the days, months and years following a major collapse.

Safety guidance for visitors

• Avoid affected routes: Park officials strongly advise climbers to avoid the East Ridge and other routes directly below unstable faces until conditions are reassessed.
• Heed ranger warnings: Follow closures and advisories posted by Grand Teton National Park and by the Jenny Lake Rangers.
• Keep distance: Stay out of known debris fields and valley locations where rockfall debris accumulates.
• Choose alternatives: The park has many lower‑risk hikes and less-traveled areas suitable for visitors who want to experience the range safely.

Park staff continue to monitor the situation. Visitors should check the official Grand Teton National Park website and social media accounts for the latest alerts and route closures before heading into the backcountry.

Sources: Jenny Lake Rangers (Instagram), Buckrail, WyoFile, Grand Teton National Park reports.