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Messages 1 - 38 of total 38 in this topic |
gstock
climber
Yosemite Valley
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Topic Author's Original Post - Jun 11, 2014 - 09:29am PT
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FYI - There was a large rockfall from the southeast face of El Capitan at about 04:30 this morning. The rockfall originated from the far eastern side of the face, slightly east of the path of Horsetail Falls but west of the East Buttress. A large block free-fell for several hundred meters then impacted hard on a lower angle slope just above the base of the cliff. This impact caused the block to pulverize, creating a very large dust cloud that filled the western portion of the valley for about an hour.
This is the same general location as rockfalls occurring in 2010, but this new source is higher and appears to be distinct from and unrelated to the 2010 rockfalls.
Using the xRez photo of the southeast face taken in 2008 before the rockfall, it is possible to get a sense of the block that failed (this, by the way, is one of the main reasons that we took those photos). The cliff before the rockfall is shown on the left, and after on the right - note that they were not taken from the same location and so are not exact replicates. Interesting that the cliff does not show obvious signs of instability in the "before" photo.
There have been no reports of injuries, but no doubt many climbers on El Cap witnessed the event. The East Buttress route and the approach to that route along the base of the cliff are temporarily closed.
Greg Stock
Park Geologist
(209) 379-1420
greg_stock@nps.gov
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Vitaliy M.
Mountain climber
San Francisco
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Jun 11, 2014 - 09:54am PT
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Sick looking roof. Klaus, one FA less for you lol
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Jun 11, 2014 - 10:42am PT
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Pitches 8-9 of Get Whacked and pitches 6-7 of Chinese Water Torture are probably quite different now. The lower pitches of Pressure Cooker and the Waterfall Route were also likely affected by the impact.
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Toker Villain
Big Wall climber
Toquerville, Utah
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Jun 11, 2014 - 10:44am PT
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Read about Bonatti on the Grand Jorasses with a hundred plus meter tower falling right over him!
The mountains are alive, but people easily forget this.
I wonder what time of year the most mass wasting occurs.
(this would have been Layton's 76th birthday; maybe its his restless spirit)
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Clint Cummins
Trad climber
SF Bay area, CA
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Jun 11, 2014 - 10:51am PT
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Wow, huge block and no apparent weakness before.
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Roxy
Trad climber
CA Central Coast
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Jun 11, 2014 - 10:59am PT
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YIKES!!!
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survival
Big Wall climber
Terrapin Station
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Jun 11, 2014 - 11:14am PT
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Yikes!
So glad no one was under that at the time!
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j-tree
Big Wall climber
Typewriters and Ledges
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Jun 11, 2014 - 12:05pm PT
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Was awoken by this from my bivy ledge on Lost Brother. VERY loud and the dust cloud moved slowly towards the meadow like creeping fog. Tried to get pictures but my little point and shoot wasn't up for the task.
Interestingly, I counted numerous parties on the nose, zodiac, and on top last night as I went to bed; only a party low on the nose bothered to wake up and look around with headlamps. The rest of the Captain was quiet and dark. Very disconcerting at the time as I couldn't see well enough to know how close to Zodiac the rockfall was.
Definite worst moment of the week came in those split seconds when I woke up on my portaledge, recognized rockfall, but didn't know if it was coming from above me on my formation or from somewhere else in the valley. Not easy to get back to bed after waking that way.
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cali kat
climber
CA
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Jun 11, 2014 - 12:13pm PT
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Pardon the El Cap naivete, but does this impact the East Ledges descent?
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Vitaliy M.
Mountain climber
San Francisco
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Jun 11, 2014 - 12:17pm PT
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Read about Bonatti on the Grand Jorasses with a hundred plus meter tower falling right over him!
He had some EPIC stories in his book. Was a true badass. Real climber.
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HighTraverse
Trad climber
Bay Area
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Jun 11, 2014 - 12:19pm PT
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East Ledges Descent is way around the corner. Nowhere near.
Interesting that Greg and Co have closed East Buttress route for now.
Hopefully erring on the safe side.
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Michelle
Social climber
1187 Hunterwasser
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Jun 11, 2014 - 12:28pm PT
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Haha V
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cali kat
climber
CA
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Jun 11, 2014 - 12:36pm PT
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Thanks, High Traverse! Glad this won't strand climbers topping out.
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Mungeclimber
Trad climber
Nothing creative to say
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Jun 11, 2014 - 12:54pm PT
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greg, to the question above, isn't most rock fall occurring in the heat of the afternoon in the early season?
Anyone have the link to Greg's posting about this?
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saa
climber
Bleau, cham, pink granite coast
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Jun 11, 2014 - 01:32pm PT
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If anyone has complaints about government employees salary being a waste of dollar, let them see this!
thanks to you, master geologist of ours.
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RyanD
climber
Squamish
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Jun 11, 2014 - 01:37pm PT
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Glad nobody was hurt.
Those before and after pics are in-sane!
Yep, looks like u gotta head back up there Klaus.
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JEleazarian
Trad climber
Fresno CA
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Jun 11, 2014 - 01:44pm PT
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Pretty scary stuff, considering how many times I've been in the impact area. Thanks, Greg, for your invaluable posts here.
John
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McHale's Navy
Trad climber
From Panorama City, CA
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Jun 11, 2014 - 03:02pm PT
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It's ridiculous that the rocks can't just stay put. It's very disappointing.
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j-tree
Big Wall climber
Typewriters and Ledges
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Jun 11, 2014 - 03:15pm PT
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sorry Ryan, the NPS failed to pay for a warranty when I established it.
+1,000,000
Klaus wins this thread
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RyanD
climber
Squamish
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Jun 11, 2014 - 03:15pm PT
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Fair enough, their loss. Never skimp on the warranty.
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Oplopanax
Mountain climber
The Deep Woods
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Jun 11, 2014 - 03:29pm PT
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hmm, that would indeed result in you getting whacked.
good name choice klaus
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vlani
Trad climber
mountain view, ca
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Jun 11, 2014 - 03:48pm PT
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cliff does not show obvious signs of instability What do you mean no signs? Any roof is an obvious sign of instability ))
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mucci
Trad climber
The pitch of Bagalaar above you
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Jun 11, 2014 - 03:48pm PT
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Nice one klaus!
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Jun 11, 2014 - 04:26pm PT
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Well, I didn't say "no signs", but I take your point vlani. I should have said that this area did not display obvious fractures in the cliff above the previously existing roof; rockfalls often detach along such bounding fractures. Compared to many, many other roofs in Yosemite Valley this one didn't seem especially prone to failure, especially in the way that it did.
Thankfully the presence of roofs doesn't necessarily indicate imminent failure...
Munge, this link has some discussion about thermal stress as a potential rockfall trigger:
http://www.supertopo.com/climbers-forum/1189611/Measuring-rock-flake-deformation
And there is also a little bit here:
http://www.supertopo.com/climbing/thread.php?topic_id=2328246&tn=0
By the conceptual model sketched out in those posts, we might expect more summertime rockfalls to occur in the late afternoon and evening when the temperature is greatest, and thus amount of flake deformation away from the cliff may also be greatest. Of course there are going to be exceptions, and today's rockfall, as well as last Sunday's rockfall from Middle Cathedral, fall into that category. There may still be a temperature link, as the other inflection point in temperature and deformation occurs in the early morning. Or, alternatively, these rockfalls may have been triggered by something else entirely.
Or, alternatively, we may have no idea what's going on up there.
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Plaidman
Trad climber
South Slope of Mt. Tabor, Portland, Oregon, USA
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Jun 11, 2014 - 05:35pm PT
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Or, alternatively, we may have no idea what's going on up there.
Classic!
Plaid
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whitemeat
Big Wall climber
San Luis Obispo, CA
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Jun 11, 2014 - 05:50pm PT
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new route potential!!!
damn good thing no one was killed!
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Rattlesnake Arch
Social climber
Home is where we park it
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Jun 12, 2014 - 07:02am PT
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Thanks, Greg, for the timely report.
It was fortunate no climbers were injured. It is not uncommon for parties to arrive at the base of the East Buttress at first light.
I assume from the description that the route itself was not damaged but the standard approach might be destabilized, hence the closures?
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pyro
Big Wall climber
Calabasas
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Jun 12, 2014 - 07:16am PT
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thanks for the report greg!
lets hope the park service keeps tourist informed.
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rwedgee
Ice climber
canyon country,CA
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Jun 12, 2014 - 08:33am PT
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" large block free-fell for several hundred meters " ????
This is America dude, El Cap is measured in feet !!
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martygarrison
Trad climber
Washington DC
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Jun 12, 2014 - 09:01am PT
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That must have made quite a boom!
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Ed Hartouni
Trad climber
Livermore, CA
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Jun 12, 2014 - 09:09am PT
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how is the lidar movie of daily movement of the cliff face coming along?
that would be a wild visual!
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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Jun 12, 2014 - 10:40am PT
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Dang. First 2.5 pitches of Waterfall Route have been annihilated!!
Keenan and Jaysen led those pitches for me.
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LilaBiene
Trad climber
Technically...the spawning grounds of Yosemite
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Jun 12, 2014 - 02:41pm PT
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Was digging the diagram & didn't see the punchline coming...just had an entire bus full of Bostonians tear their eyes away from their smahtphones, iPads, what-have-you, to turn and look at me like I'm some kind of nut job (no offense intended!) for ~gasp~ laughing.
FM you totally cracked me up! Appreciate the belly laugh. (Apparently, I laugh when I completely peel off rock, now, too. Must be age-related...) Heh.
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le_bruce
climber
Oakland, CA
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Jun 12, 2014 - 02:55pm PT
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Uf great account J Tree - hearing that booming across to the Lost Bro would be fffffffrightening.
Great and unsettling pic from Tom there, mcreel.
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Chiloe
Trad climber
Lee, NH
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EOS, a newsletter published by the American Geophysical Union, has a front-page story in the 22 July 2014 issue on "Reducing rockfall risk in Yosemite National Park." Some excerpts:
Rockfalls are common natural events in Yosemite National Park. A rockfall inventory database for Yosemite [Stock et al., 2013] documents 925 rockfalls between 1857 and 2011, resulting in 15 fatalities; 85 injuries; and extensive damage to buildings, roads, and trails. Although virtually all of Yosemite Valley is subject to rockfalls, the developed area of Curry Village, nestled among talus and large boulders, has proven particularly vulnerable. Established in 1899, Curry Village is a complex of visitor and employee accommodations, consisting mainly of rustic wooden and tent cabins. Rockfalls affected Curry Village almost from its inception, but the direct consequences became more prevalent in the past few decades [Stock et al., 2013].
A rockfall in July 1996 devastated an area just east of Curry Village when the impact of about 30,000 cubic meters of rock generated an air blast that felled 1000 trees, causing one fatality and several injuries. Rockfalls from above Curry Village in 1998–1999 caused another fatality and destroyed several tent cabins. A rockfall in December 2003 caused minor injuries and damaged 14 wooden cabins, and another rockfall from the same location in June 2007 caused additional damage. These impacts culminated in October 2008, when a roughly 5700-cubic-meter rockfall damaged or destroyed 25 wooden and tent cabins (Figure 2a). Three people sustained minor injuries, and many more narrowly avoided injury or death.
The most effective method for mitigating rockfall risk in Yosemite is to reduce exposure by removing structures from hazardous areas and by re-purposing buildings to low-occupancy uses. About one-third of all structures in Curry Village were located within the newly established hazard zone, and many were among the highest risk identified. Accordingly, the NPS removed more than 200 buildings from Curry Village in 2013 (Figure 2b). Three other buildings were repurposed from residences to storage. Elsewhere in Yosemite Valley, campsites were relocated, and other buildings were assigned reduced use levels.
The success of these mitigation actions was quickly realized. In the early morning of February 2014, a rockfall sent boulders into Curry Village, but this time, there were no lon- ger buildings there to be affected. A boulder with a volume of about 1 cubic meter impacted within the footprint of a former wooden cabin and then came to rest within the foundation of another (Figure 2c). Had these cabins been standing, they would have been extensively damaged, and had they been occupied, there almost certainly would have been injuries and perhaps even fatalities....
It is not possible to completely eliminate risk from rockfalls in Yosemite; indeed, the soaring cliffs are precisely why so many peo- ple visit the park....
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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I had a walk along the base of Waterfall Route this spring, and was amazed by the amount of rockfall! The place was unrecognizable. And looking down on it from above, I was amazed by its size and magnitude.
Greg, I have live video of the Gulf Stream rockfall from a few years ago, if you want to see it, send me an email.
I can tell you that this recent Waterfall Route rockfall was much bigger! I didn't see it, but you don't need to be a geologist to look down from high on the wall, and see the amount of terrain that got wiped out!
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