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Yosemite crack in Royal Arches

The enormous crack showed up sometime in August. Photos: Yosemite Climber Stewards/Instagram

The Inertia

Of the many climbing zones in Yosemite, Royal Arches is one of the most iconic. It’s an amazing piece of nature; a band of rock that soars towards the sky at a relatively easy grade. But climbers last month came across a new feature on the cliff: a massive crack running up the face.

Royal Arches has an interesting history. First climbed in 1936, it begins in a chimney. Once you’re past that, you hit a chockstone, then traverse over a long series of ledges until you get to a steeper, smoother face. After another traverse, you hit a finger crack that needs to be negotiated until you’re faced with a series of cracks and ledges. At the top of those pitches, climbers find themselves looking at a bolted anchor with about 30 feet of rope attached. They then have to pendulum over or climb to the left, ending up on yet another ledge system that leads to a massive hollow flake. After that, there’s just one more pitch before you’re done — but the last pitch is a real doozy. It ends interestingly, though, merging seamlessly into a trail through the woods. It’s a fun climb, but that’s not the only reason it’s so popular. It also serves as the easiest way to approach the famed North Dome.

According to Yosemite park officials, the huge new crack, which as of this writing is about 200-feet long, is still actively cracking. They’ve closed sections of the park because it has affected the integrity of a rock pillar that sits beside one of the more popular Royal Arches routes known as the Super Slide. The National Park Service closed trails on August 30, and they’ll remain closed until they can get a handle on the cause and what to do about it.

“We learned about this [new crack] from a Yosemite Mountain School guide who had climbed up there on August 6 and did not see the crack,” Jesse McGahey, a Supervisory Park Ranger at Yosemite National Park, told Climbing. “And then he climbed it on August 20 and the crack was there. And it was a finger-tips to one-inch sized crack 200 feet long or so.”

The next week, a climbing ranger who is also a geologist went to get a first-hand look. McGahey went on to say that ” they could hear it cracking like a frozen lake that wasn’t consolidated.”

Of course, it’s not all that uncommon for rock faces to crack, and there are a variety of reasons for why they do.

“Triggering mechanisms like water, ice, earthquakes, and vegetation growth are among the final forces that cause unstable rocks to fall,” the National Park Service explained. “If water enters fractures in the bedrock, it can build up pressure behind unstable rocks. Water also may seep into cracks in the rock and freeze, causing those cracks to grow. This process is called ‘frost wedging’ or ‘freeze-thaw’ and can incrementally lever loose rocks away from cliff faces.”

According to reports, the crack is moving about an inch per week. As is often the case with things like this, though, it’s tough to predict what the future holds.

“The large pillar of rock that has park officials worried could be about to drop, or it could take years,” wrote IFLScience, “but until they have a clearer picture of the potential threat, parts of the park will remain out of bounds.”


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