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gstock
climber
Yosemite Valley
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Topic Author's Original Post - Mar 26, 2012 - 03:45pm PT
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Hi all,
Cleo and I are working on updating the database of Yosemite rockfalls, which now runs from 1857 to 2011 and has over 900 entries. I'm trying to track down information on a few rockfalls that I know happened, but for which we have no database entry.
First, I'm wondering about the date (year, and also month and/or day if known) of a rockfall from El Capitan that took out part of the route "Space"? The approximate source area is shown in yellow in the photo below. I think this happened in the late 1990's or early 2000's, but as I say we have no date for this event listed. Anybody know something about this rockfall?
Next, I'm wondering if anybody knows more about the rockfalls from Quater Domes over the past few decades? Both domes show evidence of recent exfoliation-type rockfalls, and the Reid guide lists 1997 as the year the one on the eastern dome occurred. Anybody have more specific information on that event? Or know anything about when the rockfalls on the western dome occurred? Seems like at least one of those occurred prior to 1998.
Finally, I'd like to open it up to any other reports you may have about rockfalls that you were witness to anywhere in Yosemite. We probably have records of the larger ones (i.e., no need to report the 1996 Happy Isles rockfall), but if you witnessed smaller ones, especially in remote areas of the Valley and/or prior to 2006, then there is a strong possibility we do not have a record of it. I would need at least the year of occurrence, and preferably the month/day or season. It would also be helpful to know the location as specifically as possible, an approximate size (ok to use size examples like toaster oven, washing machine, VW bus, school bus, battleship, etc.), and what the environmental conditions were like (e.g., sunny, rainy, earthquake shaking, etc.). Feel free to post your observations here, or send me an email.
Thanks!
Greg Stock
Yosemite Geologist
(209) 379-1420
greg_stock@nps.gov
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nutjob
Gym climber
Berkeley, CA
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Mar 26, 2012 - 03:57pm PT
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June 2005, early morning, huge fall off Northwest Face of Halfdome. Just after sunrise, sleeping in manzanita on top and east of North Dome Gully. Awoke to sound of fighter planes blitzing the valley. It was the sound of lots of rock whizzing down before a series of big slams (kind of like the garbage trucks emptying a dumpster, but louder) and a rolling thunder. From about 1/2 or 2/3 way up, right of center face. We saw new stuff detaching and mid-air, after the initial impacts. Dust cloud was so big it filled the valley all the way over to Glacier Apron area. I never heard a big news thing about it. My buddy may have gotten video footage of the very tail end and the dust cloud.
Anyone anywhere on the slabs approach to HD would have been ground into paste.
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Fluoride
Trad climber
West Los Angeles, CA
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Mar 26, 2012 - 05:50pm PT
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Bad rockfall on Middle Cathedral just above the catwalk, spring of '04. Was around 11am on a Saturday in May (was up there when it happened). Most of it came down almost directly onto CP of Frenzy and amazingly no one got hurt. Base was splattered with all the debris. Left a noticeable scar on the place where it fell from. Chunk was probably truck sized.
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Mar 26, 2012 - 07:48pm PT
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Thanks for the reports!
Nutjob, I have an entry for a rockfall on June 19, 2005 at 5:45 am, which sounds like the one you described except that it was reported as coming from the the Porcelain Wall rather than from the NW face of Half Dome. However, the reporting party didn't see the rockfall, only the dust and surmised that it came from the Porcelain Wall. From your description it sounds like it would be better to change that to the NW face?
Fluoride, in case you haven't already seen it, here is a photo of the rockfall you witnessed from Middle Cathedral, which happened on May 15, 2004:
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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Mar 26, 2012 - 07:53pm PT
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I've got videos from BUBS on El Cap when the first two pitches of Gulf Stream fell off. The talus rolled a quarter-mile downhill, and the dust cloud was as high as the Nose.
I had them posted on Youtube, but Kate made me take them down. She was all wide-eyed saying, "Holy #$*(@in' #($*% - I was just up there two weeks ago with Erik!"
Did you ever see those? I could email. Send me a PM.
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KabalaArch
Trad climber
Starlite, California
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Mar 27, 2012 - 12:24am PT
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Well, my recollection is hazy with time, but this is an important topic.
The first release I recall was above the 2/3’s point of the Yosemite Falls trail, which resulted in a hiker’s fatality. I thing this was about 1979. The scar above the trail is quite evident.
Shortly thereafter was a release from Eagle Pk, which is still unstable, rendering the Koko’s area too dangerous to climb. This preceded the release about The Folly by 20 years.
Rockfall activity has been increasing at GPA for at least 25 years. First came the release which stripped Monday Morning Slab of all of its mature trees – including the rap tree on the ledge which traverses over to the Point Beyond upper start.
Then, Happy Isles. My partner and I happed to be about midheight Tightrope when a football exploded about 10 feet climber’s left of the 2nd belay…this was about 2 years prior to the catastrophic realease.
Then came the Hinterlands release, which resulted in fatalities from a party on Apron Jam. Historic photos exist of this rockfall – I’ve viewed some taken from S Face Washington. A civil lawsuit was filed against the NPS, alleging that the proximate cause of this rockfall was due to the installation of a new septic./leachfield installation during the course of the GP improvements. But, the findings were that the leachfield effluent was pretty nominal compared to annual spring snow meltw#ter runoff.
I have some post-release photos of the 9 O’clock Wall incident.
The Crane Flat Road was closed on one occasion, due to rockfall at Reed’s area., which covered the westbound lane…this was in about 1990 or so.
According to Matthes, the GPA is composed of Half Dome quartz monzonite, while the Hinterlands is Sentinal granitdiorite. And these two strata are shifting west to east with respect to once another – The Oasis occurs at the bedding seam.
Apparently, the young Sierra is still growing – by my information, Tioga Pass is a full 12 inches taller than it was when I was 14. This is good, because the geologists’ maps I’ve seem, to guide future construction in the Valley, show a talus outfall zone which encroaches about 15-20% onto the Valley floor. In geologic time (which is happening now), this means that the Valley cliffs will eventually be reduced to talus slopes, unless the uplift of the Sierra exceeds its erosion.
Some folks feel that earthquakes help remove debris from ledges, etc. Others claim that earthquakes add more debris.
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Clint Cummins
Trad climber
SF Bay area, CA
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Mar 27, 2012 - 03:03am PT
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- East Quarter Dome: 1994 or later, because Bill Wright's 1994 trip report doesn't mention any loose rock:
http://www.wwwright.com/climbing/tripreports/1994/QuarterDome.htm
 West Quarter Dome: 1993 or earlier, because the 1993 guidebook "Yosemite Climbs: Big Walls" has a photo on p.147 showing the "rockfall area" on West Quarter Dome with a label. (while the East Quarter in the same photo shows no big rockfall scar yet).
Which Reid guide are you referring to which gives a 1997 date to the East Quarter Dome rockfall? The Free Climbs guide is 1994. Is it in the 1998 "Yosemite Select"? I think 1997 is about right. There is a slightly vague post on the Quarter Dome thread from Steve Grossman mentioning Quarter Dome and 1997. He may be able to supply more details.
These posts on rec.climbing indicate that the East Quarter rockfall had occurred by 1999, and John Black stated that it occurred 3-4 years before that:
Dingus Milktoast Jul 12 1999, 11:00 pm
I've been wanting to ask a secondary question (there are TR's
about 1/4 Dome by the way, on Tuan's web page if I'm not
mistaken)...
Looking down Tenaya Canyon from the Meadows, Burl and I noted the
massive rock fall scar on 1/4 Dome. Thing is... I don't remember
seeing it before. Now I have altered more of my brain cell
structure than is advisable and I may be suffering a memory lapse.
But my question is... how old IS that huge rock scar... to the
right of, I believe, the East Face route?
DMT
John Black Jul 12 1999, 11:00 pm
There was a big rockfall about 3-4 years ago on the North Face of East
Quarter Dome. I THINK it has since been climbed, but I'm not sure. I've
heard that the lower 3 pitches of the North Face route are gone. If I were
you, I'd be careful going into that area... it's like glacier point apron
but steeper! :)
-------
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Fluoride
Trad climber
West Los Angeles, CA
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Mar 27, 2012 - 04:37am PT
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Greg, yeah I think I saw that pic. Thanks for posting it again. Man that was nasty. I was stunned no one was hurt by it. A sunny May Saturday morning at the height of the season with Frenzy in it's path. Crazy stuff.
I remember there was a dog at the base that some climbers had leashed to a tree or something and he was missing. The rockfall cut the leash and the dog was found later that day safe and sound back near Camp 4. He ran away from the scene in time.
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BooYah
Social climber
Ely, Nv
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Mar 27, 2012 - 09:35am PT
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Space rockfall was in '95 or '96, I believe. It took the whole 8th pitch.
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Mungeclimber
Trad climber
the crowd MUST BE MOCKED...Mocked I tell you.
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Mar 27, 2012 - 11:22am PT
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Bump
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j-tree
Big Wall climber
Classroom to crag to summer camp
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Mar 27, 2012 - 11:48am PT
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Has anyone been on Space since the rockfall?
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BooYah
Social climber
Ely, Nv
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Mar 27, 2012 - 11:58am PT
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It's been done at least twice since that time, j-tree.
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Mar 27, 2012 - 11:58am PT
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Thanks for the 1992 Surgeon General report, Klaus; we have no record of that.
The prominent scar on the west face of Mount Broderick is from several rockfalls occurring in July 2003. That's the scar on the left in the photo below. The larger scar on the right on Liberty Cap is from a rockfall that was triggered by the March 26, 1872 Owens Valley (Lone Pine) earthquake. That rockfall produced an airblast that knocked Snow's Hotel, located at that time below Liberty Cap, off its foundation by a few inches.
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j-tree
Big Wall climber
Classroom to crag to summer camp
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Mar 27, 2012 - 12:02pm PT
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It's been done at least twice since that time, j-tree.
Thank you. Did either team report as to what pitch 8 entails now?
(sorry to hijack the thread, this is my last question about this I promise. It's just hard to find info on Space because of the clutter you get when searching for a route name as common as the word "space.")
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BooYah
Social climber
Ely, Nv
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Mar 27, 2012 - 12:04pm PT
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My beta comes from Jay Selvige(spelling?) Topo says "many bathooks, loose; pitch missing".
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Mar 28, 2012 - 09:46am PT
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Thanks everyone for your responses. I'm still hoping for more specific dates for the "Space" rockfall on El Cap? 1994 versus 1995? Summer versus winter?
One way to go about pinning this down would be too go through any photos of that area from the mid 1990's and try to bracket when the scar appeared. I have a lot of photos from the 1970's and post 2006, but that doesn't bracket it very well.
Here's an offer (made outside of my position as park geologist): Anyone that can nail down the year and season of the "Space" rockfall gets a free copy of "Geology Underfoot in Yosemite National Park": http://mountain-press.com/item_detail.php?item_key=524
Thanks!
Greg
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scuffy b
climber
heading slowly NNW
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Mar 28, 2012 - 12:13pm PT
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May 1975, Somewhere near the big Zodiac circle, but I don't know exactly.
Two falls in the same day. The second one produced a lot of dust.
From six pitches up on Middle Cathedral, our view of Sentinel was totally
obscured. A couple boulders made it just about to Northside Drive.
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Melissa
Gym climber
berkeley, ca
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Mar 28, 2012 - 12:30pm PT
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Greg...I ask my husband about Space. He did what he thinks is the 2nd post-fall ascent with Chris Trudeau in the summer of 1998. To the best of his memory it was done once after the fall "the previous season" but doesn't recall exactly when that was...so climbing season 1997. The first post-fall ascent was "relatively recent" after the fall. His best guess is it fell in Spring 97 and was climbed by fall 97.
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Mar 28, 2012 - 07:24pm PT
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Thanks Melissa, that is very helpful. I'll wait a bit longer see what others may say, but if no more information comes in I'll be asking for your mailing address!
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Mighty Hiker
climber
Vancouver, B.C.
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Mar 28, 2012 - 07:25pm PT
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The rockfalls from El Cap Tree area, starting spring 1977? Or did someone mention them already?
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Melissa
Gym climber
berkeley, ca
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Mar 28, 2012 - 09:02pm PT
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No worries. Did we win a prize?! :-)
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Minerals
Social climber
The Deli
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Mar 28, 2012 - 10:07pm PT
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Wasn’t the Space rockfall in January? I don’t remember exactly, but have a vague recollection that it was during winter. ’97 sounds about right; it was in the late ‘90s. The fresh talus and mangled oak trees were covered with a ton of rock dust for at least a few months after the event and there were a bunch of impact marks on the slabs below The Alcove where the blocks first impacted.
Roger and I heard the rockfalls on 6/13/99 and 6/15/99 on Glacier Point while we were on the Falls Wall. 10:13 PM sounds right for the second rockfall (as listed in the database that Clint linked to); I remember hearing it around 10 PM.
The first A5 Adventures catalog has a hand-drawn topo on the inside of the back cover – “El Capitan, S.E. Face Topos” – and the Footstool rockfall is listed as ’78. I’m not sure if this is correct or not. There have been several releases out of the Footstool scar, some as recent as the last 5 or 10 years because the talus keeps changing. The sharp, mega tombstone that was so cool is no longer standing at the base; it was right up next to the wall, on the far right side of the scar, at the edge of the trees. Greg, it’s the tombstone that Kent is leaning against in Figure 6. (C) in his 2001 GSAB paper (to be specific…).
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gstock
climber
Yosemite Valley
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Topic Author's Reply - Mar 29, 2012 - 12:56pm PT
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Just for persepctive, January 1997 was during the big flood, after which the park was closed for many weeks for repairs. Does this timing sound right for the Space rockfall?
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Melissa
Gym climber
berkeley, ca
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Mar 29, 2012 - 01:35pm PT
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I sent a note to Chris. Maybe he'll remember more.
Have you guys sifted through old rec.climbing posts? Might be something there.
This one wasn't as big as the others, but it was kind of a wild realization...In August of 2002, I think, MInerals led us on geology tour. We went to the base of Mecca to see "his favorite rock", but it was missing. I was taking a load off on a big boulder, and when I looked next to where my butt was parked, there was a 3/8" bolt and hanger affixed. My seat had apparently replaced the favorite rock. He could probably tell you when his last visit to the not-yet-smooshed rock would have been.
The moderate (compared to the one on the right side from Aug. 2006) sized fall I saw from by Trundling Juan was likely March 2004.
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Minerals
Social climber
The Deli
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Mar 31, 2012 - 05:22pm PT
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Greg, that sounds about right, but again, I am not 100% sure. I suppose it could have also been in February. If the rockfall occurred while the park was closed for repairs after the flood, then there obviously wouldn’t be any climbers around to witness the event. Is this why none of us can really remember exactly when it was? Where’s Werner and his internal database of Valley history?
I seem to remember talking to climbers about the rockfall in the spring, not too long after it happened, and no one knew exactly when it cut loose but figured that it was in January because when they showed up in late winter/early spring, it had already occurred. The flood peaked on January 2nd, so it would make sense if the extraordinary amount of rainfall and snowmelt took a few days or a couple of weeks to seep through the fracture systems on El Cap and eventually contributed to greater freeze-thaw action. But I really don’t know for sure…
Questions: With respect to diurnal fluctuations of the surface temperature of the rock on El Cap, would this be greater during the winter than in the summer? During the summer, nighttime air temperatures are relatively warm and even though daytime air temperatures can be really hot, the angle of the sun is fairly oblique to the vertical surface of El Cap. During the winter, nights are much longer and air temperatures dip well below freezing, yet the sun is much lower in the sky and so the angle of the sun is much more direct on the face of El Cap. On clear winter days, sunlight would quickly warm the surface of the rock on El Cap while the south side of the Valley would remain shaded and frigid. But, how about the effects of colder daytime air temperatures and convection? The base of El Cap can feel like a toaster in the winter while El Cap Meadow feels like an icebox (although this is also due to a temperature inversion). Does this make any sense?
How do heating rates of granitic rock compare to cooling rates of granitic rock when in direct sunlight versus when in the shade/dark, and how much of a factor is rock albedo? We would expect dark diorite to reach a higher temperature than light granite when in direct sunlight, but I am curious about heating and cooling rates.
With a quick Google search, I found some answers here:
http://web.unbc.ca/~lindgren/pdf/hall_et_al_2005.pdf
(Edit: POS box of electrons doesn’t recognize the entire link… Copy and paste…)
Yeah, Melissa, that was fun! Here’s a photo of part of the boulder that was still intact in ’98 or ’99. It was pretty cool looking – coarse-grained gabbro (related to the Diorite of the Rockslides) that was brecciated by the intrusion of numerous aplite/leucogranite dikes. Too bad it was decimated. It seems that there have been several releases from Lower Cathedral Rock over the last couple of decades.
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