Discussion Topic |
|
This thread has been locked |
Karl Baba
Trad climber
Yosemite, Ca
|
|
|
Nov 22, 2008 - 04:21am PT
|
"Yosemite geologist Greg Stock, hired three years ago mainly to study the rockfalls, said the incident last month indicates the professors are incorrect in theorizing that human water use is to blame. "
Does this mean they will reopen the mega-expensive bathrooms that are locked up next to the porta-potties?
Peace
karl
|
|
-Skip
Mountain climber
|
|
|
Nov 22, 2008 - 10:10am PT
|
Rokjox - As far as I know, there hasn't been human wastewater "pumped" into the cliffs for several years. I haven't heard of anyone claiming that recent slides were caused by that. Seems to me that you're also right, pumped wastewater would only influence a percentage of the falls, "releasing them early" compared to the longer timing of nature without help. -Skip
|
|
StevenJ
Trad climber
Norcal
|
|
|
Nov 22, 2008 - 10:18am PT
|
Hello Supertop Crew!
I've been lurking for about a year. I climbed in the Valley a lot as a teenager in the mid-80's so it's fun to see that some of you I used to recognize in Camp 4 are still around! (I guess I was luring there too.) Many posts remind me of the "glory days" and I've actually, gasp!, started climbing again with my kids.
I recently read an article Doug Robinsion wrote called "The Atomic Broom Theory", http://www.adventuresportsjournal.com/html/Articles/45/alpinism.htm
In it he talks about how the rock fall in the Sierras accelerated due to atomic testing in he Nevada desert and this left the mostly solid rock of the 60's, 70's etc. to climb on. He goes on to state that rockfall is increasing because enough time has passed for stuff to start getting wedged off of the faces on a regular basis again.
Interesting but I'm not sure I buy it.
Any thoughts? I'd love to hear from Greg Stock on this if it's been considered. The data on the spreadsheet that Greg posted doesn't appear to support this idea but I would think the reporting of rockfall is probably more complete now than it was in the 30's, 40's and 50's.
If it's true that atomic bombs make for better climbing let's start testing again! (JUST KIDDING!!)
sj
|
|
gstock
climber
Yosemite Valley
|
|
|
Nov 22, 2008 - 11:29am PT
|
Geologists and hydrologists from the U.S. Geological Survey have investigated the issue of wastewater at Glacier Point in detail. Their results show that the amount of wastewater available for infiltration at Glacier Point is miniscule compared to amounts of natural rainfall and snowmelt. Unfortunately, because of the ongoing litigation, they have not yet been able to publish their findings, and so the media coverage of this issue has been very one-sided.
It was interesting to read in the AP article that the stated human influences on Glacier Point rockfalls have switched from wastewater to the parking lot and unspecified "construction". I presume this is because none of the recent rockfalls can be plausibly linked to wastewater in any way. The shifting arguments for what triggers Glacier Point rockfalls suggest a determination to blame these rockfalls on human activity no matter the circumstances.
Water does not appear to have played a role in triggering the October 7 and 8 rockfalls. The detachment area was dry when photographed immediately after the rockfalls, and when viewed from a helicopter about an hour later. This rules out wastewater, and also parking lot runoff, etc., as possible triggers.
I’ll follow up on Greg Barnes’ historical note with this one. The first documented rockfall from Glacier Point was made by the famous geologist Joseph LeConte, who wrote: “Soon after leaving camp, Soule and myself, riding together, heard a big rumbling, then a crashing sound. ‘Is it thunder or an earthquake? Looking up quickly, the white streak down the cliff of Glacier Point, and the dust there, rising from the Valley, revealed the fact that it was the falling of a huge rock mass from Glacier Point.”
The year of LeConte’s observation? 1870.
The month? August.
Greg
|
|
gstock
climber
Yosemite Valley
|
|
|
Nov 22, 2008 - 11:39am PT
|
StevenJ, I’ve got some issues with the “Atomic Broom Theory”. The May 1980 Mammoth Lakes earthquakes triggered thousands of rockfalls in the Sierra Nevada (Harp et al., 1984, USGS map I-1612), including at least nine here in Yosemite Valley. The atomic broom must not have been very efficient if it left that much loose rock to be dislocated in 1980. Even if the loose rock were “swept away” in the 1950’s, it would take far longer than a few decades for the granite to be substantially weathered again. Think about all that pristine glacial polish in Tuolumne Meadows – it’s 18,000 years old, a product of the Tioga glaciation, but it looks like it formed yesterday. In Yosemite Valley we still see the effects of the Tioga glaciation on the spatial variability of rockfall – most of the large rockfalls occur from above the glacier trimline where the rocks are more weathered.
That is not to say that atomic testing didn’t change our world in fundamental ways (isotopes in the hydrologic cycle are but one eye-opening example), but I doubt that it had much impact on rockfall in the Sierra Nevada.
It’s a beautiful day in Yosemite Valley - I’m out the door.
Greg
|
|
StevenJ
Trad climber
Mill Valley CA
|
|
|
Nov 22, 2008 - 01:01pm PT
|
Thanks Greg!
sj
|
|
Wade Icey
Trad climber
www.alohashirtrescue.com
|
|
|
Nov 22, 2008 - 02:24pm PT
|
rock falls in the valley every day and night. some days and nights more than others.
|
|
-Skip
Mountain climber
|
|
|
Nov 22, 2008 - 06:38pm PT
|
“Unfortunately, because of the ongoing litigation, they (government geologists) have not yet been able to publish their findings, and so the media coverage of this issue has been very one-sided.”
That’s what I don’t like about litigation, or even the fear of litigation. It gets in the way of sharing useful information and slows the answering of questions needed to protect the public. That’s so counterproductive.
As for the press, reporters often over simplify or confuse the fine points. Only the general pictures get through. The experts need to be allowed to sit down together and compare what they know with open minds unhindered by attorneys, so they can each begin to grasp what the others have been saying.
There’s more to Glacier Point rockfalls than there’s room for in news bites. But comparing concentrated point-source wastewater in a sensitive location to non-point source rain and snowmelt is like comparing apples to grapes. Which is which? Sadly, it looks like a court might have to decide.
|
|
gunsmoke
Trad climber
Clackamas, Oregon
|
|
|
Nov 30, 2008 - 11:43pm PT
|
I'm amazed that Mighty Hiker's observation has been basically ignored:
"With the closure of the river and other campgrounds, there are far fewer campsites in the Valley than 25 years ago. This will further restrict the numbers of visitors. Lots of significant policy consequences."
Yosemite Lodge cabins, River Campgrounds, and now a third of Curry, gone? (Anyone remember Muir Tree Campground?) No doubt many cheer this as a another step toward getting the Valley under control. For me, the Valley is a lost cause insofar as being a primitive experience. (If we were to limit access sufficiently to return to a primitive experience, the average Joe could get a once-in-a-lifetime, three day visit by winning a lottery.) If the NPS is going to take out a third of Curry, it's time to ask for public input as to whether to close or to relocate the affected cabins.
|
|
enjoimx
Big Wall climber
SLO Cal
|
|
I think the left arete will go!
|
|
|
SuperTopo on the Web
|
Let us know!