Middle Cathedral Rock-Fall 3/16/2013!

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Messages 1 - 34 of total 34 in this topic

Vitaliy M.

Mountain climber

San Francisco

Topic Author's Original Post - Mar 18, 2013 - 10:30pm PT

Did anyone else see it? Knows anything about it?

Happened mid day. Just left of the water streaks which split the formation in half. Was very loud and had a lot of stuff coming down. I got my camera out just after majority of it passed..

pell

Trad climber

Sunnyvale

Mar 18, 2013 - 10:39pm PT

We were approaching El Cap base. I did a couple shots.

Seems it was not too far from DNB.

It happened around 10:45am.

cleo

Social climber

the canyon below the Ditch!!!!

Mar 18, 2013 - 11:36pm PT

Make sure gstock gets a good report!

le_bruce

climber

Oakland, CA

Mar 18, 2013 - 11:42pm PT

From 3 pitches up. Looked like it came down right over the North Buttress route. Loud for sure, but maybe not huge in terms of material released? Good reminder, in any case, of the many ways that we all spin the roulette wheel day in and day out in life.

donini

Trad climber

Ouray, Colorado

Mar 18, 2013 - 11:56pm PT

Vitaliy....shore those cliffs up, i want some climbing left when i get there in May.

GDavis

Social climber

SOL CAL

Mar 19, 2013 - 12:36am PT

quick, check the base for new bad ass talus bouldering!!!!! If it is so good in RMNP there has to be some awesome blocks sitting at the base waiting for your radness***, and probably still warm, too!

Clint Cummins

Trad climber

SF Bay area, CA

Mar 19, 2013 - 10:49pm PT

Yes, it looks like it came down the North Buttress.

Adamame

climber

Santa Cruz

Mar 19, 2013 - 10:51pm PT

Looks pretty small compared to some of the rockfalls in that are from past years. Good thing there are raptor closures over there right now.

survival

Big Wall climber

Terrapin Station

Mar 20, 2013 - 12:21am PT

Good thing I wuz waring muh helmet and muh shouldamuhpads. Oh, and my cup.

Fat Dad

Trad climber

Los Angeles, CA

Mar 20, 2013 - 12:24am PT

Some 30 yrs. ago, I was on the East Butt. of MCR and some rockfall came down the Spires gully. The volume and cacaphony was just crazy. Still very vivid all these years later.

TomCochrane

Trad climber

Santa Cruz Mountains and Monterey Bay

Mar 20, 2013 - 12:34am PT

the biggest rockfall i've ever experienced seemed like a few of tons of boulders crashing around past us while sitting on top of Dolt Tower in 1985

limpingcrab

Trad climber

the middle of CA

Mar 20, 2013 - 12:54am PT

Who's gonna get the FA of that new tan spot!?!

lucander

Trad climber

Shawangunks, New York

Mar 20, 2013 - 01:49am PT

I heard that the guy who has been chipping in the Gunks has been in California.

Sierra Ledge Rat

Mountain climber

Old and Broken Down in Appalachia

Mar 20, 2013 - 02:51am PT

Yes, it looks like it came down the North Buttress.

1+

Looks like a direct hit
Wonder how the route changed

gstock

climber

Yosemite Valley

Mar 20, 2013 - 03:30pm PT

Thanks for the report and great photos. There have been many rockfalls from Middle Cathedral in the past two years. Happily I've already ticked the North Buttress!

A couple of years ago we measured talus volumes beneath several of the major cliffs in the Valley, and then normalized the volumes by the size of the cliff above it. This allows us to directly compare long-term rockfall activity from the different cliffs over the past 15,000 years or so. The results, listed in terms of more rockfall to less rockfall are:

1. El Capitan (Salathe Wall)
2. Cathedral Rocks
3. Middle Brother
4. Glacier Point
5. Royal Arches

Interesting that Glacier Point, which has a reputation for rockfall, actually has had fewer rockfalls (or at least smaller rockfalls) over time than El Capitan. This highlights how much our individual experience colors our perception of hazard and risk. We evaluated this pattern with respect to many different variables and found the best correlation with degree of glaciation - basically, the cliffs that were extensively glaciated have had fewer rockfalls, most likely because the fractured, weathered rock in those areas was cleaned off by glacial erosion.

Greg Stock
Park Geologist
greg_stock@nps.gov
(209) 379-1420

Clint Cummins

Trad climber

SF Bay area, CA

Mar 20, 2013 - 03:37pm PT

I'm surprised about the result for the Salathe' Wall. Do you really mean El Cap Gully and face over to Ribbon Falls (left of the West Face of El Cap) as the source of the talus field? I am thinking the big slope under El Cap Gully / West Face / SW Face is different rock (e.g. KP Pinnacle) from El Cap itself (say West Face). I'm thinking this different granite mix type collapsed a long time ago. Vs. continually fell off of El Cap right until the present.

I'm not sure if that normalization for "rockfall activity rate" works so well for Glacier Point, because about half of its height is a very smooth slab that should not produce any major rockfall. The upper half, with the trees, etc. should be where the rockralls come from. And when they come down, they won't be slowed down much by barriers on the slab!

[Edit:] Thanks for the extended answers, Greg!

There are a few different rates which could be calculated, due to the dimensions like frequency over time, volume, etc.
For example, the huge rockfall event out of the NA Wall:

huge on the volume scale

maybe small on the frequency of time scale

I guess we climbers may perceive risk on the frequency over time scale, for volumes large enough to kill us.

Is there a way to use the size of unforested talus slopes as an indicator of active rockfall areas?

How would the huge unstable talus slope under Nuts Only Cliff figure on your activity rate scale?

gstock

climber

Yosemite Valley

Mar 20, 2013 - 03:54pm PT

Clint, our calculation was for just the talus underneath the Salathe Wall proper, exclusive of debris that came from KP Gully or from the Ribbon Falls area. It surprised me too, but look at the size of that talus pile!

One big unknown though is exactly where the bedrock is under the talus. We investigated this at Glacier Point with geophysics (seismic, resistivity, and ground-penetrating radar) and found that the talus there was sitting on river sediment. But we haven't done that at El Capitan, so it's possible that the volume is large because some of it is bedrock.

Regarding Glacier Point, you are correct that the Apron has had very few rockfalls (there is still glacial polish there). However, even when we exclude the lower portion of the cliff area below the glacial trimline, the adjusted rate is still somewhat lower than El Capitan.

The problem with the talus of the Rockslides area (Nuts Only Cliff) is that it was downvalley of the maximum extent of recent glaciation, so it has been accumulating for much longer.

Greg

Clint Cummins

Trad climber

SF Bay area, CA

Mar 20, 2013 - 04:04pm PT

It's cool that there are still many basic unknowns like the bedrock level under the slope below the SW Face of El Cap.
The slope still doesn't look like an "active rockfall slope" to me because of the trees. More like a "historic rockfall slope"?
Perhaps it's my bias to the time dimension here again.

gstock

climber

Yosemite Valley

Mar 20, 2013 - 04:12pm PT

Perhaps, but check out this post:

http://www.supertopo.com/climbing/thread.php?topic_id=474787&msg=2089881#msg2089881

JEleazarian

Trad climber

Fresno CA

Mar 20, 2013 - 04:15pm PT

Clint,

I remember heading up toward La Escuela in the early 1970's, and the base of the southwest face of El Cap looked like someone had bombed it. I believe that particular rockfall was from a couple of pitches of the Heart Route.

I am rather surprised that the Three Brothers, and particularly the east side of Lower and Middle brother, are not higher on the list. The area to the left (southwest) of Rixon's Pinnacle has always been known as a bowling alley, and I remember rockfall around The Folly that added another Bear Rock sized boulder or two to the talus field.

In any case, those pictures of the Middle Cathedral rockfall made me wonder if Thirsty Spire or The Turret are still attached. Ever since Sentinel Spire bit (or, more accurately created) the dust, I've always wondered about last ascent possibilities.

John

Edit: Checking Greg's reference to the thread on the Heart Route confirmed that the rockfall came from that route. Apparently, the white tower (aka Tower to the People) and some associated pitches simply fell off.

BASE104

Social climber

An Oil Field

Mar 20, 2013 - 04:24pm PT

Greg,

You could do a totally non-invasive 3D seismic survey of the entire valley. Now the geophones are wireless and the energy source could be vibraseis on the roads.

I've never seen a 3D shoot of anything like this, especially with the velocity problems that you will get with talus, which could be large. Weathered zones such as any alluvial deposits are really tough to correlate. It would be interesting.

In the meantime, yep, El Cap has huge talus depostits on both sides of the Nose. If you have ever humped the approach all the way to the W Buttress, you have to go uphill a long way.

Things that are above sea level are always heading downstream and downhill. I would love to work on the stratigraphy of the glacial and alluvial deposits in Yosemite.

gstock

climber

Yosemite Valley

Mar 20, 2013 - 05:17pm PT

Base, I would love to do that, especially since the only previous seismic investigations of Yosemite Valley occurred in the 1930's (published in 1956): http://gsabulletin.gsapubs.org/content/67/8/1051

My efforts to fund such a study have thus far been unsuccessful.

Clint Cummins

Trad climber

SF Bay area, CA

Mar 20, 2013 - 06:04pm PT

those pictures of the Middle Cathedral rockfall made me wonder if Thirsty Spire or The Turret are still attached.

They're definitely still there and not coming off anytime soon.
If one of them came off, the road would be blocked.

A good reference for comparison are the July/September 2011 rockfalls which came off the North Face, slightly left of Mother Earth.
They generated a lot of dust and deposited a lot of small rocks/gravel all along the base when the source flakes disintegrated on the way down.
But Greg's photos pinpointed the sources as some relatively small flakes.
http://www.supertopo.com/climbing/thread.php?topic_id=1552021

In the 90s I was at the base of El Cap and saw a very similar (to 3/2013) rockfall come down the North Buttress of Middle, with lots of dust. It was sobering, because we were planning to do the route in the next day or two. We made other plans. :-)

In the late 80s I saw some boxcar sized blocks come down the middle of the North Face from the band of overhangs up high. Big impact craters at the base.

The height from which the rocks fall in the Valley is another dimension to the rockfall risk (besides frequency and volume).
It leads to devastation at the base!

Largo

Sport climber

The Big Wide Open Face

Mar 20, 2013 - 06:09pm PT

I'm amazed that Middle doesn't just fall over some time. It was always my favorite rock by I cut back my time on the big faces there after Billy Westbay got beaned one time when we were on the DNB and Kauk and I almost got cleaned off Stoner's by a big ass rock slide from the U-Shaped Bowl. We were down low and I rapped off the rope to the ground and just took off running, right off the end of the line as sh#t continued raining down.

JL

Bruce Morris

Social climber

Belmont, California

Mar 20, 2013 - 07:07pm PT

Sometimes Middle around Stoner's is as quite as a mouse. Sometimes a couple of basketballs come down there without any warning. Just keeps you on your toes. But then there's that north apron area . . . big stuff waiting to happen.

Norwegian

Trad climber

the tip of god's middle finger

Mar 20, 2013 - 07:13pm PT

is it really just a sloppy interaction
between gravity and the adhesive / cohesive
forces of the mountain's resolve?

perhaps there are mountain gnomes
than can come and go from our plane
as they please; and these gnomes,
they've personalities and tempers
and sex and suicide, just like us.

perhaps if you pay proper homage to
the mountain prince, rockfall aint gonna
gather in your path?

perhaps if you mastrabate twice in the
bush directly below their blow hole,
they can be adequately please of your
enlightened passage?

im trying it next go.
good thing i aint partners,
and i go solo on these
awkward understandings.

KabalaArch

Trad climber

Starlite, California

Mar 20, 2013 - 07:26pm PT

I - that is: "Willy and I": - have had quite a few footballs and toasters sail past us on the MCR Apron over the years. It's very important to remain focused when these UFO's come hooting past 'yer run.

A couple of years ago we measured talus volumes beneath several of the major cliffs in the Valley, and then normalized the volumes by the size of the cliff above it. This allows us to directly compare long-term rockfall activity from the different cliffs over the past 15,000 years or so.

You don't have to be Matthes to realize that, some day, the entire Valley shall be refilled into the vee-shaped river gorge whence it came; I've seen some of the geotech's maps of the max talus outfall zones, which seem to exclude only Sentinel Beach - and scarcely so, at that.

Question on point seems to be: is this going to occur before Tioga opens this season?

TomCochrane

Trad climber

Santa Cruz Mountains and Monterey Bay

Mar 28, 2013 - 12:45am PT

One day in the mid 1960's, Jim Mays returned to Camp 4 on his old bicycle with wide eyes and rock dust in his hair. He came up to my camp by the Wine Boulder and told about riding down the road towards El Capitan past Rixon's Pinnacle, when boulders the size of semi-trucks started bounding down across the road all around him. Some rather large pot holes were punched into the road and some boulders blocked the road for a while. We walked back there together and he showed me the fresh rock fall boulders.

I've mentioned earlier about experiencing a major rock fall coming down all around us on Dolt Tower in 1985.

Another day in the early 1960s I walked from Camp 4 up to the base of the Nose of El Cap early in the morning after a big ice storm. When the sun hit the upper face, large sheets of ice started melting and falling down directly towards me, fluttering around like heavy falling maple leaves. On either side of me there were great slabs of ice crashing into the forest. Those that came directly down the nose were pulverized by impact with the rock and reached me as a shimmering curtain of ice crystals in the sunlight.

I've spent many days on Glacier Point Apron and on the Cathedral Rocks without any recollection of rock fall.

gstock

climber

Yosemite Valley

Jun 10, 2014 - 05:55am PT

Heads up that there was a rockfall from Middle Cathedral on Sunday morning, June 8, 2014. Several "car-sized" boulders fell from near the top of the Direct North Buttress. Debris swept the DNB and areas to the east, almost as far east as the Central Pillar of Frenzy.

mikeyschaefer

climber

Yosemite

Jun 10, 2014 - 11:19am PT

Any photos of the suspected release zone Greg?

gstock

climber

Yosemite Valley

Jun 10, 2014 - 11:30am PT

A climber who witnessed the rockfall from the first pitch of the Nose sketched it out like this:

I haven't yet been able to pin down an exact source area.