El Capitan rockfall 11 June 2014

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Messages 21 - 39 of total 39 in this topic << First  |  < Previous  |  Show All  |  Next >  |  Last >>
j-tree

Big Wall climber
Typewriters and Ledges
Jun 11, 2014 - 03:15pm PT
sorry Ryan, the NPS failed to pay for a warranty when I established it.

+1,000,000

Klaus wins this thread

RyanD

climber
Squamish
Jun 11, 2014 - 03:15pm PT
Fair enough, their loss. Never skimp on the warranty.
Oplopanax

Mountain climber
The Deep Woods
Jun 11, 2014 - 03:29pm PT
hmm, that would indeed result in you getting whacked.
good name choice klaus
vlani

Trad climber
mountain view, ca
Jun 11, 2014 - 03:48pm PT
cliff does not show obvious signs of instability
What do you mean no signs? Any roof is an obvious sign of instability ))
mucci

Trad climber
The pitch of Bagalaar above you
Jun 11, 2014 - 03:48pm PT
Nice one klaus!
gstock

climber
Yosemite Valley
Topic Author's Reply - Jun 11, 2014 - 04:26pm PT
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...

Credit: Roger Putnam


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.
Plaidman

Trad climber
South Slope of Mt. Tabor, Portland, Oregon, USA
Jun 11, 2014 - 05:35pm PT
Or, alternatively, we may have no idea what's going on up there.

Classic!

Plaid
whitemeat

Big Wall climber
San Luis Obispo, CA
Jun 11, 2014 - 05:50pm PT
new route potential!!!

damn good thing no one was killed!
mcreel

climber
Barcelona
Jun 12, 2014 - 03:58am PT
In a recent El Cap report, there is this very nice photo

http://www.elcapreport.com/sites/default/files/2%29%20%20CNIMG_3613.JPG

which appears to show a very large and very scary looking block to the L of the belay above Sickle ledge on the Nose. Is that thing as bad as it looks? Brrr!
Rattlesnake Arch

Social climber
Home is where we park it
Jun 12, 2014 - 07:02am PT
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?
pyro

Big Wall climber
Calabasas
Jun 12, 2014 - 07:16am PT
thanks for the report greg!

lets hope the park service keeps tourist informed.
rwedgee

Ice climber
canyon country,CA
Jun 12, 2014 - 08:33am PT
" large block free-fell for several hundred meters " ????

This is America dude, El Cap is measured in feet !!
martygarrison

Trad climber
Washington DC
Jun 12, 2014 - 09:01am PT
That must have made quite a boom!
Ed Hartouni

Trad climber
Livermore, CA
Jun 12, 2014 - 09:09am PT
how is the lidar movie of daily movement of the cliff face coming along?
that would be a wild visual!


'Pass the Pitons' Pete

Big Wall climber
like Ontario, Canada, eh?
Jun 12, 2014 - 10:40am PT
Dang. First 2.5 pitches of Waterfall Route have been annihilated!!

Keenan and Jaysen led those pitches for me.
LilaBiene

Trad climber
Technically...the spawning grounds of Yosemite
Jun 12, 2014 - 02:41pm PT
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.
le_bruce

climber
Oakland, CA
Jun 12, 2014 - 02:55pm PT
Uf great account J Tree - hearing that booming across to the Lost Bro would be fffffffrightening.

Great and unsettling pic from Tom there, mcreel.
Chiloe

Trad climber
Lee, NH
Aug 6, 2014 - 02:25pm PT
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 19981999 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....
'Pass the Pitons' Pete

Big Wall climber
like Ontario, Canada, eh?
Aug 6, 2014 - 04:51pm PT
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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