Enormous Rock Slide Blocks Yosemite Entrance Points

Spencer Miller | | WeatherWeather
Aerial photo of the slide courtesy of Yosemite National Park Service.

On June 12, 2017, an estimated 4,000 ton rock fell onto the “Parkline Slab” cliff and shattered.  The impact created a landslide effect that ran right over highway 140 and down to the Merced River, blocking entry into Yosemite National Park.  El Portal Road and Arch Rock Entrance remained closed at this time, and will reopen on June 17, at the earliest.  Get road updates from Yosemite National Park.

Photo courtesy of Yosemite National Park Service.

Read the official press release from the Yosemite National Park Service below: 

“The El Portal Road and Arch Rock Entrance into Yosemite National Park remain closed due to a rockslide that occurred yesterday around Noon. Yosemite National Park staff are assessing the area and the road will remain closed at least through the weekend of June 17-18, 2017. After the assessment is complete, crews will begin to remove rock debris and repair the road to make it safe for visitors to travel on. There is no estimate for when the road will reopen.

Around Noon yesterday, a large rockslide occurred from the “Parkline Slab” cliff, about 1 mile east of the park boundary on Highway 140.The rockslide originated from a point mid-way up the cliff, approximately 400 feet above the base of the cliff and 600 feet above the El Portal Road.

Roughly 4,000 tons of rock detached from the cliff along a cliff-parallel exfoliation joint; the approximate dimensions of the slab are 50 x 80 x 15 feet. This massive slab of rock slid down the cliff, hit a ledge, and broke into many pieces; these pieces fragmented further on hitting the base of the cliff, fanning out over an area more than 1,000 feet wide. The bulk of the debris slid and rolled down the slope at the base of the cliff, piling up on the El Portal Road, and continuing down to (and into) the Merced River.

Of the total volume of material that fell, roughly 1/3 of that landed on the El Portal Road, covering an area of road about 150 feet long under up to 15-20 feet of rock debris. The largest boulder on the road is about 130 tons, and there are several other boulders that are only somewhat smaller. Boulders and smaller “flyrock” fragments covered a section of road nearly 1,000 feet long. The road sustained damage, both to the paved surface and the retaining wall.”

Where the original fell from. Photo courtesy of Yosemite National Park Service.

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