No easier way to terrify yourself than banging the palm of your hand on a flake, and hearing a sound that sounds like a drum. That's when you realize you're hanging on many tons of rock not ain't much attached to anything.
17
Imagine many of these thin cracks on this massive rock face, holding water that continually freezes and melts...the freezing of water causing expansion and exerting massive pressure pushing the walls outward.
Relying on these skins of rock to keep you alive seems a precarious proposition at best.
Foolhardy or courageous?
9
“When you’re standing on them, it’s really quite amazing to think that this is just perched on the side of El Capitan and for some reason it’s still there,” he [Brian Collins] said.
My wife describes the entire-body-sensation of standing at the precipice of sheer drop-off of anything more than 7 or 8 feet as "Ookie!"
I'm good for about 10 or 12.
5
Save the face of the dome! Clearly man is accelerating its demise. Our desires should not always be satisfied at the expense of nature.
9
@Lori Millet Sure, blame it on humans.
At least you aren't blaming continental drift on humans, since that has been occurring long before man was on Earth, and will continue long after.
15
When walk up to the base of El Cap (and most other faces) you are walking over pieces of former flakes.
16
Finally a scientific explanation of why I almost scared myself to death on Half Domes North West Regular: There's a flake about a quarter of the size of El Caps Boot Flake - and when I tried to chimney upwards this giant rock just startet moving off the wall. Fortunately I got on top of the flake before sending it down to the wall's base ...
16
@Frank Understanding the rock isn't a prerequisite for climbing it?
3
It's not as complicated, or as static, as is intimated by these supposed experts, surprisingly. It's simply exfoliation, a dynamic process.
Much of Sierra granite is termed "exfoliated granite." A more accurate term would be "exfoliatING granite."
24
I realize making climbing the face off limits won’t help though it should. There was the base climber years ago who perished because base climbing was more important than the effect of viewing splattered people to onlookers or passers by.
The sheer face should signal not only "l myself am up to that," it should answer the question as to how it got to be a sheer face in the first place.
Well, as a species we’re nothing if not daredevils, are we?
4
Until you stand at the base of El Capitan and look up, you have no idea what this monolith is really like. It made me marvel at the courage of climbers who have the guts to scale the sheer face. Now with this news of flakes, I wonder if fewer climbers will attempt the adventure.
6
My brother is one of those guys who climbs El Cap. He’s been up at least two dozen times. I sent him this article and his reply was as this: “You know I’ve climbed the Nose four times! It doesn’t worry me at all. Also, there are far larger flakes on El Cap than Boot and Texas.” So if you think this is going to stop climbers from climbing El Cap, the answer is no.
21
Thermal imaging, please!
23
Thermal imaging is often misused, and misconstrued, but in this case I think it's correct. The misuse comes from interpreting the derived temperature data due to temperature only. The other variable is called "emissivity", which is the departure of material's radiant emission signal from an ideal "black body", whose emissivity is equal to one. When thermal imaging is used in industrial settings, changes in emissivity in the scene can be confusing. In this case the material being observed is only granite, which has some emissivity value, which I don't know, but it is all granite, with no changes in rock which could provide apparent temperature differences which aren't real. I would believe this study to be significant, and a very good use of thermal imaging technology. One can now purchase thermal imaging cameras using microbolometer arrays, which are quite good.
13
El Capitan is an example of an exfoliated dome and probably exfoliated tor. Its rock is granite, an igneous rock that cooled tens of miles below the surface. There, the minerals making up the rock were at equilibrium. However, when uplifted to its present exposure, the pressure at formation is greatly reduced at the surface. As a result, some of the minerals expand, causing "layers" like those of an onion, and allowing the detachment of rock sections. Additionally, daily temperature changes on the climbing surface cause additional expansion and contraction of the minerals. Perhaps the surprise is that there aren't more rockfalls.
49
@mweaver "...when [El Capitan] uplifted to its present exposure,...." When I was a young boy and frequent visitor to Yosemite Valley, rangers explained that the Valley was formed by glacial scouring, and that's what exposed the gorgeous granite monoliths so familiar to us -- El Capitan, Half Dome, Liberty Cap, etc. This explanation downplayed eons of preceding geological activity -- uplift -- which moved the granite monoliths toward the surface, facilitating their ultimate exposure by glacial scouring. Now we know that both forces at work over geological time -- uplift and scouring -- shaped the Valley as it is today. Thanks to mweaver for reminding us of this fuller explanation of the Valley's formation.
46
@mweaver "Perhaps the surprise is that there aren't more rockfalls."
"More" is a relative term. In the geologic context, there are as many rockfalls as appropriate to the exfoliating process. Geologic time is more patient than we humans' perception of it. It seems slow to our busy minds. But it's also relentless.
The onion peels slowly. But the peels fall away suddenly. It's just a matter of time...
10
@Rocky
Geological time includes now.
9