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mucci
Trad climber
The pitch of Bagalaar above you
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Apr 15, 2011 - 07:28pm PT
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Funny, one of the only places I have NOT been in rockfall is the GPA.
My partner did find a ASCA bolt head, sheared off at the base of something to the right of grack.
Washington Column is by far the worst wall in the park. I have been in 4 (Big enuff to make you think YER GONNA DIE!)rockfalls on both sides of the column.
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wildone
climber
Troy, MT
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Apr 15, 2011 - 07:30pm PT
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I have never been more scared than when my partner and I were bombarded with massive amounts of ice and rock from about 1000 feet above us on the east butress of Whitney. Luckily, we lived. I can still remember the sound.
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Karl Baba
Trad climber
Yosemite, Ca
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Apr 15, 2011 - 07:45pm PT
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I have to say, I've seen a lot more rockfall on Middle Cathedral, and even El Cap than the apron
Any giant cliff has rocks coming off of it. Yosemite is better than any alpine climbing environment for rockfall though, so it's all relative
Peace
Karl
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gstock
climber
Yosemite Valley
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Apr 15, 2011 - 08:07pm PT
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An important caveat to the notion of precipitation as the most common rock fall trigger in Yosemite is that this is true only when compared to other recognized triggers. More than half of all of the rock falls in the database (now current through 2010, and soon to be available as a USGS Open-file Report) do not have recognized triggers. This means that a reliable connection could not be made between a rock fall and an environmental condition such as seismicity, precipitation, freeze-thaw, etc., even in cases where the rock fall was closely observed. Because rock fall detachment surfaces are rarely instrumented when failures occur, in most cases assigning a rock fall trigger is not an exact science.
Many unrecognized triggers are associated with summertime rock falls, where we suspect the effects of thermal stress (heat) may play a role. So it could actually be that thermal stress is at least as important as precipitation in triggering rock falls in Yosemite.
It's also important to remember that people tend to more influenced by events that they witness or are directly involved in, as opposed to events they only read or hear about. The recent rock falls at Glacier Point are surely part of our collective conscience as a community, but the fact is that rock falls occur virtually everywhere in Yosemite Valley. Our measurement of talus volumes suggest that long-term (post-glacial) rock fall rates are actually greater at El Cap, the Cathedrals, and Middle Brother than they are at Glacier Point or Royal Arches.
Ultimately I tend to agree with Ed's sentiments expressed above.
Greg
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gstock
climber
Yosemite Valley
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Apr 15, 2011 - 08:46pm PT
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That is really difficult to determine. Reporting of rock falls has generally been good (not perfect) since about 1980, but even that is a short time period with respect to geologic processes. We have compared historic rock falls rates with the longer-term rates from talus, and they generally match up, but there are large discrepancies in areas like Middle Brother, where a 600,000 cubic meter (1.8 million ton) rock fall occurred in March 1987, skewing meaningful comparisons over such disparate time periods.
We are in the process of dating a number of the large boulders on the floor of the valley (like Columbia and LeConte boulders) and this should give us a better sense of rock-fall activity that occurred before than the historical record but on shorter timescale than overall post-glacial talus accumulation.
Greg
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Jan
Mountain climber
Okinawa, Japan
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Apr 16, 2011 - 12:03am PT
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I don't remember any concern about rockfall in the 1960's.
Were we just naive or was it a golden age in that respect as well?
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Captain...or Skully
climber
My ready room
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Apr 16, 2011 - 12:10am PT
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You were gonna die, you just didn't know it.
Or some such.
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xtrmecat
Big Wall climber
Kalispell, Montanagonia
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Apr 16, 2011 - 12:15am PT
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Like it has been stated prior, it is relative. Last May I had way more rock fall on elcap than the apron. This Jan. Had more on elcap than then. These climbing days were relatively safer than almost every other outings I had this year, most of which were Canadian alpine, or alpine in nature. The valley shedding stones seems very benign to some of us used to other stuff also. Wear a helmet for sure.
Burly Bob
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Clint Cummins
Trad climber
SF Bay area, CA
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Apr 16, 2011 - 12:34am PT
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Maybe slight off topic:
Helmets are fine, but they do not increase your survival chances by much if it's a big rockfall.
Better to simply avoid those higher risk areas, if you can identify them and don't mind choosing another climb.
Helmets may be helpful if you take a leader fall and hit your head.
But they may also increase the chances that you will feel willing to risk such a fall.
They are fairly good for protecting against gear dropped by someone above you, but such stuff can still hit you in the face/nose....
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StahlBro
Trad climber
San Diego, CA
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Apr 16, 2011 - 12:46am PT
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Exfoliation is a bitch.
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pyro
Big Wall climber
Calabasas
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Apr 16, 2011 - 01:15am PT
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i've never seen a graph about the rock fall surrounding the Yosemite Valley.
quite impressive!
i'll show my friends.
thanks Greg.
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TomCochrane
Trad climber
Santa Cruz Mountains and Monterey Bay
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Apr 16, 2011 - 02:22am PT
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the best protection is always listening to hear it coming and have your head somewhere other than the arriving rocks
hats and helmets distort sound
i've noticed helmets tend to have dents in them
i have no dents in my head and haven't experienced a time when a helmet would have helped
Edit: several routes that i've climbed have fallen down and no longer exist; including El Cap Tree Direct, North Face of Lower Cathedral Rock, and the Gendarme at Seneca
i've twice dodged major rockfall on the Grand Teton; once on El Cap, once on Lower Cathedral Rock North Face, once on Rixon's, and others in the mountains...with innumerable smaller stuff
never saw rock fall on GPA, which is one of my favorite areas of Yosemite
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Brokedownclimber
Trad climber
Douglas, WY
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Topic Author's Reply - Apr 16, 2011 - 09:54am PT
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Jan-
When we were there in 1965, I do recall some rockfall over near Koko Ledge. Much of it was initiated by Air Force jets "buzzing" the Valley.
Maybe this is one of the reasons that I've been doing smaller cragging over the intervening years? Vedauwoo, City of Rocks, and Joshua Tree.
P.S. (added in edit): Eldorado has some rockfall too, but is mostly initiated by climbers knocking stuff off ledges.
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mouse from merced
Trad climber
merced, california
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Apr 23, 2012 - 12:13am PT
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I never go to the Apron area unless there's a body to retrieve
-Werner Braun
Zo, ze voice of visdom zpeakz to uz in ze gize of ze voice of eggsperience.
LISTEN UP!
Wer-nerds to hear words like this
They shouldn't stand around and piss.
Instead do this:
Run away! Run away!
ALL KNIGHTS: (taking up the cry) Run away! Run away!
-contributed by Ed Cartoony (Spanky and the gang at the Cookie)
"that's all, folks?" you are Looney Tunes
Be a chicken, be a rabbit,
Mice run away, force of habit.
The racket and tumult of rockfall is grand. I have been lucky to see just the one from Elly Rock in Dec. 1970. This is the one Millis always talked about, and it happened in mid-morning. The next one in that location was in March 1971 and happened in the middle of the night. I checked the history and those are the dates. The second event was three times the volume of the one Millis and I witnessed. We were climbing Stigma in 1970.
Millis was on A3 placements, poor sod lived to tell of it, thankyewJC. In the even greater rockfall we were bivvied on the Leaning Tower. It woke me and I woke Millis. We just knew what it was without thinking much about it, but when we found out where, we cringed. If you ever get to see such a magnificent display of Nature consider yourself lucky.
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