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WBraun
climber
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Topic Author's Original Post - Jul 2, 2005 - 12:03am PT
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Use caution on the approach slabs from mirror lake to the base of Half Dome. The rock scars to the right of Tissack are active again. They went off earlier this evening.
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Minerals
Social climber
The Deli
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Weren’t we just talking about… How cool.
Werner, on average, over several years, would you say that more rock fall in the Valley occurs in the summer months or the winter months?
Hot day + rapid evening cooling (since HD gets the last sunlight of the day) = POP! Differential cooling rates within an already unstable rock mass…? Singer must be right! Our world is falling to pieces!
More pictures?
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WBraun
climber
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Topic Author's Reply - Jul 2, 2005 - 12:36am PT
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I'm not sure Brian, it seems it's happening all times of the year. But .... something real big blew off over by the diving board about a week and a half ago real early in the morning, 6:45 am or so. There was a huge cloud of granite dust about that time. I don't know exactly where it came off at that location.
I actually witness that big one below El Cap tree years ago, El Cap tree direct. Me, Chris Falkenstine, and Marko Milane ran the hundred meter dash in world record time when that sucker blew above, all while laughing nerviously. We were at the right side of the footstool when it took off. We were watching a rurp crack become 4 + inches in about a couple of hours and then the whole thing went.
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Minerals
Social climber
The Deli
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Thanks, Werner.
Diving Board? Between the Bushido Gully and the top the Porcelain?
Or the Visor by the top of the Reg?
So maybe the lower Kali Yuga scar formed earlier this winter and the rock fall that occurred about a week or so ago came off of the Diving Board area?
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WBraun
climber
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Topic Author's Reply - Jul 2, 2005 - 12:47am PT
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Not quite sure as I only saw the end result a huge cloud of dust. Someone on shift went over to check it out but didn't get the exact rockfall location.
But, .... I pretty sure from the diving board area, left of Bushido.
Kali Yuga scar, I don't know about that one.
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Minerals
Social climber
The Deli
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Cool. Thanks for all of your updates, Werner. I’m sure everyone else appreciates them too. Shack and I were discussing the rock falls/scars on HD, based on his pictures from his last visit. Hopefully Shack won’t mind if I ‘borrow’ his picture that best shows the two most recent rock scars. (If not I’ll nuke it!)
photo by Shack
The upper scar has been active for the last couple of years (as you know, Werner) but the lower scar (the ‘Kali Yuga scar’) seems new to me.
Hey Werner, you guys have probably seen it and any of the park geologists who are supposedly monitoring this stuff (USGS) should have seen it… but there is a fat crack running to the NE, from the summit area of the NE side of the Porcelain Wall, towards the Bushido Gully. This crack (about #3 - #4 Camalot size in width) runs for about 100 yards or so. It is the foot pathway to cross the slabs from the top of the PW to the BG. Cold air blows up from the crack. The crack separates a giant wave of overhanging rock from the main mass of the buttress between the two walls; this same crack can be seen on the face, below the summit. The mass that overhangs is something like half a city block. It sticks in my memory as the most precarious large mass of rock that I have seen in the Park. I’m not suggesting any kind of intervention, as the efforts over the decades to support “The Man in the Mountain” on Cannon Cliff in New Hampshire have proved unsuccessful. It may outlive all of us, but when it does come down, that sucker is going all the way to the river. Hope your tourists aren’t in the way…
How about some high-tech, solar powered, digital video cameras, mounted in key locations to monitor active rock scars (in addition to the seismic sensors already installed)? The computerized system would record video – this video would be computer-edited over time (maybe daily?) to remove excess data (periods of no activity and periods of no daylight) such that the system would be triggered to save video when any major visual motion occurred (any size rock fall). The computerized video camera systems would be ‘semi-permanently’ installed in optimum locations (such as the high-precision GPS stations that I come across out in the desert). Maybe they could have a real-time satellite link-up for constant monitoring and alarm notices? So how ‘bout it, big money government? How bad do you want to protect your tourons? You can’t suck more money out of ‘em once they are dead…
Curry Village? Megadeth (like the band…) waiting to happen with the next serious tremor. NPS got life insurance?
http://landslides.usgs.gov/html_files/landslides/Yosemite99.html
http://landslides.usgs.gov/html_files/pubs/report1/gsa_bulletin_yosemite.pdf
http://pubs.usgs.gov/of/1998/ofr-98-0467/
http://pubs.usgs.gov/of/1999/ofr-99-0578/
From the above link:
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WBraun
climber
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Topic Author's Reply - Jul 2, 2005 - 01:47am PT
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Well you know that animal (upper scar) looking rock scar just to the right of the slanting Tissack corner it looks different when I looked at it before dark. The upper left side of that animal looking scar at its neck went this time.
Brian, you should be the geologist here ……..
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Minerals
Social climber
The Deli
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We were watching a rurp crack become 4 + inches in about a couple of hours and then the whole thing went.
No way!!! Rad!
Klaus told me about when he and Cosgrove were at the base of the Footstool, working on a free route. They heard some loud cracks and a little while later, the chandelier on the Surgeon cut loose and went to the deck. Walt climbed that thing. Must be cool to watch your routes fall to the deck while at the base...
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Minerals
Social climber
The Deli
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Thanks again Werner! But I would need to take at least one course in rock fracture mechanics before anyone would give me a job. Those guys know way more than I do... I just get to see the stuff up close!
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JuanDeFuca
Big Wall climber
Chatsworth
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One day the whole Leaning Tower is going to come down.
Is that not a large fault that forms the ledge that heads up to overhang bypass?
Rockstar
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Minerals
Social climber
The Deli
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One day Yosemite will be flat.
But until then...
Juan, which Bypass? A planar fracture that has undergone at least several meters of linear translation would be called a fault (aligned slickensides, mineral lineations, fault gouge and breccia, etc.). Most of the major planar features in the Valley (the face of Half Dome, the approach traverse up to the WFLT, Indian Canyon, etc.) represent the control of joints (fractures) or joint-sets on the topography. The Valley itself was formed as fluvial and glacial systems took advantage of pre-existing weaknesses in the bedrock - the current shape of the Valley is just an exaggeration of these structural weaknesses. Joints form in a rock mass primarily during the cooling stages of pluton formation (an individual magma intrusion at depth in the crust (many plutons make up a batholith, hence the Sierra Nevada Batholith…)) as well as during regional uplift.
There are sections of granodiorite in the Bushido Gully itself, where the rock has been altered to a pinkish color (K-spar 'pink' color) along the margins of mineralized joint planes. These fractures provided pathways for fluid flow and the formation of secondary minerals during the final/post stages of pluton formation. These fluids chemically reacted with the surrounding host rock/minerals to form the altered margins. Epidote, the pistachio-green-colored mineral, is one of the most common of the fracture-filling minerals, and is quite commonly seen around the Valley. Who wants to climb the GEEK Tower?
http://gsa.confex.com/gsa/2005CD/finalprogram/abstract_84505.htm
http://gsa.confex.com/gsa/2005CD/finalprogram/abstract_85268.htm
http://gsa.confex.com/gsa/2001CD/finalprogram/abstract_4953.htm
http://gsa.confex.com/gsa/2001SE/finalprogram/abstract_4818.htm
Regarding the last link, I heard a rumor about blasting on top of Glacier Point by NPS for development just before/during the GP rock fall that killed the climber... Any truth to that one???
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climberweenie
Trad climber
San Jose, CA
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I witnessed the large rockfall on HD 2 weekends ago. It was between 5:30-6am. Got some photos right afterwards, and some video at the tail end of it. Will post up when I get the pics from my buddy (from the same dude who has pics of the rattlesnake eating the squirrel which I also promised to post).
Here's my earlier post about it:
http://www.supertopo.com/climbing/thread.html?topic_id=78552#msg78552
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Roger Breedlove
Trad climber
Cleveland Heights, Ohio
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Brian, have you read the reports on the law suit associated with the June 13, 1999 rock slide on Glacier that killed Peter Terbush?
The interesting part, as reported the July issue of Climbing, is the sewage and water over flowing the Glacier Point treatment plant that may have caused the slides.
Roger
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Lambone
Ice climber
Ashland, Or
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That rockfall map is awesome! A GIS student's dream project!
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Minerals
Social climber
The Deli
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Roger, I didn’t know there were any lawsuits associated with the ’99 death at GPA. Do you have any links or info to share? Of course, the geo reports online suggest natural causes for groundwater infiltration, such as thunderstorms and snow melt…
I remember those rock falls/rockfalls/rock-falls on GP in ’99. One night, maybe 10 or 11 pm, when we were up on the Falls Wall, another section came down. There was a big rumble and a few minutes later we could see the huge dust cloud, by the ‘Lights of Curry’ as the dust cloud settled to the ground. This would have been within the week following the June 13 rockfall, because we topped out on the 21st.
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August West
Trad climber
Where the wind blows strange
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"The interesting part, as reported the July issue of Climbing, is the sewage and water over flowing the Glacier Point treatment plant that may have caused the slides."
Ok, I read this also. My first thought was, "how could the sewage and water over flow be significant compared to all the water from snowmelt?"
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Ed Hartouni
Trad climber
Livermore, CA
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Here's an image for comparison taken in February 2002
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golsen
Social climber
kennewick, wa
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Great shots! A good perspective on geology in action. As climbers, I hope that none of us becomes too actively involved in the local geology, like the poor guy who should have been wearing his helmet at GP.
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smitty
Trad climber
Santa Cruz, Ca
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I noticed this rock fall on a hike up there. When did it begin?
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Roger Breedlove
Trad climber
Cleveland Heights, Ohio
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Brian,
All I have read is what is published in Climbing, July 2005, pages 35-37. The research is from Skip Watts and a graduate student Dan Gilliam. There is a reference to a paper given by Watts and Gilliam in 1999 to the Association of Engineering Geologists in Salt Lake City. I could not find it on line.
According to Climbing, the NPS disputed the findings of the paper based on changes in the bathroom location prior to 1999.
But, if I am reading it right, since that time, the parents of the climber who was killer have received information (FOIA) that show that water--up to 150,000 gallons flowed into Glacier Point a watershed outside of Glacier Point in the weeks just before the November 1998 rock fall. I do not have the chronology down, but apparently the November 1988 slides were the first of several that included the one that killed the climber on 13 June 1999.
Aside from the interest in the science in the water pressure and its effects on the rockslides, I hope that the Federal Judge does not find the NPS negligent--it could be the end to climbing freedom in the Valley.
Roger
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