Monday, October 11, 2010

Rock Fall Near El Capitan in Yosemite Today

Your on-the-spot geological reporter was on the scene and on the job today when a rock fall occurred on the cliff just east of El Capitan in Yosemite Valley. Well, ok, I was almost on the scene, and almost on the job...to be honest, I was near the top of Sentinel Dome on the south rim of the valley, eh, dozing on the smooth granite slope. I was listening to what I thought was an odd-sounding jet off in the distance, but when the sounds abruptly stopped, I thought "rockfall!". I ran to the edge of the cliff just in time to see the dust rising from the tumbling boulders.
There has been little in the way of official information as of yet, but it seems to have originated in the vicinity of the cliff at Horse Tail Falls, the high vertical wall just east of the main cliff of El Capitan. I only had time for a cursory examination, but I think the impact point is the white rock on the cliff just above the tips of the trees.

There are white streaks on the dark gray cliffs above the white rock that may be impact scars(click on the photo below for a larger image), and lots of fresh looking boulders on the slope below. I can't tell if trees were snapped off or not. I would appreciate any reports or additional from climbers, hikers, or anyone who was in the meadow below. I will gladly post any pictures, too!
Once a big chunk of rock breaks off a cliff, nearby rocks may be destabilized, and subsequent rock falls are possible. Clearly the climbers know this...

5 comments:

Kathy Crawford said...

Always ready for the up-to-the-granite Geo-news Garry. Thanks for the cool photos... still waiting on the Geo-calander fund raiser, (hint, hint, wink, wink)

yosemite faith said...

thanks for the update and photos. you should post these on facebook and twitter - didn't see any photos like this posted about this rockfall. love the info! i am yosemite obsessed of course.

Gaelyn said...

You really were Johnny-on-the-spot. Looks like a fresh rock fall. How lucky to be so close, but not too close. Geology always surprises the most when experienced.

Just had a visitor report hearing HUGE rock fall from an overlook on the Walhalla Plateau. No confirmation.

Luke Crawford said...

It is crazy that you post this because the park Geologist from Yosemite came to UOP the other day and spoke to our department about the hazards of rock falls in yosemite and the efforts they are taking to mitigate these hazards. Thanks for posting!

Glenn Tussy said...

Hello,
Thanks for your work. I am going to link your site in a blog on my website.
www.yosemitehistorian.com