Summary (tl;dr)

A rapidly expanding rock fissure in Yosemite National Park's Royal Arches formation has prompted temporary closures of trails and climbing routes, raising significant safety concerns about potential rockfalls.

Essential Background

Yosemite National Park, nestled within California's Sierra Nevada Mountains, is renowned for its towering granite cliffs and dramatic valleys, largely carved by glaciers over millions of years. The park is naturally dynamic, experiencing over a thousand rockfalls in the past 150 years as a result of geological processes like exfoliation, frost wedging, erosion, and seismic activity. These rockfalls are a continuous force reshaping the landscape.

The Full Story

In August 2023, rock climbers discovered a new and actively widening crack, dubbed "Super Natural," on the Royal Arches cliff face in Yosemite National Park, near the popular Super Slide climbing route. Initial reports indicated the fissure was about an inch wide and 200 feet long, with park officials noting that a large pillar of rock was partially detaching. Geologists and climbing rangers observed the crack emitting sounds "like a frozen lake that wasn't consolidated" and noted small rocks falling without external intervention, signaling ongoing instability. The fissure has shown unusual and rapid growth, widening to almost four inches by August 2024, a speed considered unprecedented by park geologists. Due to the escalating rockfall risk, the National Park Service has implemented temporary area and trail closures, affecting routes like Super Slide and Serenity Crack, to ensure visitor safety.

Why It Matters

The rapid and unusual progression of this rock fissure poses a significant and potentially deadly risk of a major rockfall, making public safety a paramount concern for park officials. The active closures directly impact climbers and hikers, restricting access to some of the park's iconic areas. Furthermore, this geological event has sparked global travel concerns, with potential ripple effects on the tourism industry, including airlines and local hospitality businesses anticipating a decline in visitors to one of the United States' most popular national parks.

Geographic Location

• Royal Arches (western side, near Super Slide climbing route, north of The Ahwahnee, actively widening rock fissure and related closures), Yosemite Valley, Mariposa County, California, United States