Tom Wood
A gigantic crack has appeared in a rock formation in Yosemite National Park, resulting in authorities to close off some parts of the park whilst they attempt to figure out what is going on.
Of course, these sorts of things do occur naturally all the time, so there’s no particular worry about it, but if it was to continue cracking – as seems to be the case – it could cause a pretty dramatic and potentially dangerous event.
You wouldn’t want to be standing underneath it when this rock came tumbling down, that’s for sure.
An investigation into the Yosemite crack, which was discovered by climbers, concluded that the cracking is still actively happening, and therefore a bit of the park has had to close down just for safety reasons.
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The crack has detached – in part at least – a large pillar of rock near to a climbing route that is called ‘Super Slide’.
That’s why the 200-feet-long crack has been nicknamed ‘Super Natural’.
In order to reduce the risk to life from rockfall, some trails have been shut by the National Parks Service, starting on August 30 and continuing until further notice.
Jesse McGahey, one of Yosemite’s Supervisory Park Rangers, told Climbing: “The following week a climbing ranger and a geologist observed it first-hand and they could hear it cracking like a frozen lake that wasn’t consolidated,
“And there were pieces of rock rattling down the crack without touching it.
“The park geologist said they’d never seen anything like this. He’s never been able to observe that in his 15 years in Yosemite.”
Over the course of a seven-day period, the crack seemed to move around an inch, which – in geological terms – is a lot.
Still, it could take years for any huge pillar of rock to fall, or it could happen really soon.
We just don’t know, that’s the thing.
Until more is known, safety precautions have to be taken.
Yosemite is no stranger to events like this, as with most of the US' national parks.
The cliffs at the park were carved by glaciers, meaning that the landscape is in a constant state of flux and change.
However, you’d still want to know if there was about to be a massive rockfall.
The National Park Service explained: “Triggering mechanisms like water, ice, earthquakes, and vegetation growth are among the final forces that cause unstable rocks to fall,
“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.”
Worth keeping an eye on, then.