Basic Landslide Primer

Deep Seated Landslides

Did you know there are different types of landslides per the Geological Survey? I did know from just living here that there were surface ones, debris flows, mud flows and ones that show up months after the rains have stopped as Mud Creek did on 5/19/2017. (Yes, I know Caltrans says it happened on 5/20, but it happened after 5 pm on the 19th, when no Caltrans workers were around. Inga Dorosz of Gorda Mountain both witnessed it and photographed it as it was happening and sent it to me.) What I didn’t know, is what they were called — Deep Seated Landslides. As Daniel Swain explains (see below Mud Creek photos) we are likely to be subject to more of these this year due to the extensive rainfall we have received, and the rapidly developing El Niño we will experience next winter.

For more information on Mud Creek see: https://www.usgs.gov/media/images/mud-creek-landslide-may-27-2017

Daniel Swain (@Weather_West)

Daniel Swain (@Weather_West) in his virtual office hour on Monday, discussed the differences between mudslides and debris flows and deep seated landslides. It can be found starting at 24:28 of his you tube here: https://www.youtube.com/live/eaT1GcF2cwE?feature=share

If you are not familiar with Dr. Swain, he is well worth your time. He is a climate scientist and meteorologist and is very talented in taking complex scientific concepts and explaining them for lay persons. He looks like a teenager, but don’t be fooled. He is brilliant.

USGS and Big Sur

And for a more in-depth understanding of the rock slides specifically of Big Sur, the US Geological Survey put together a video two years ago one might enjoy here: https://www.usgs.gov/media/videos/active-landsliding-and-rock-strength-controls-along-big-sur-coast-ca

This is a fascinating and in-depth scientific study of the landslides our portion of the coast. Many of the landslides we have been experiencing this year; Paul’s Slide, Mud Creek, and other areas are presented in this 2021 video. I recommend this video for all of your who are curious about what building a highway on the edge of a continent is like and the challenges faces by Caltrans in keeping it open.

Slide Maps of the Big Sur Coast

Also, just to remind you, there is a detailed map in three parts showing all the slides, their names and positions, and photos for some of them listed to the right under pages, or, you can just click here: https://bigsurkate.blog/big-sur-interactive-highway-maps-with-slide-names-mile-markers/ Thanks to my “mystery map maker” Lucas Ryan of CV, who created them. One follower on FB said of him, “Omg, whomever created this is a genius..”

7 thoughts on “Basic Landslide Primer

  1. This information is so valuable. Thank-you, Kate. Going to study this today as this rainy day moves forward increasing the likelihood of these slides. I agree with you about Dr. Swain: looks like a kid, and he is totally brilliant and a most able, sensitive communicator.

  2. There needs to be more able communicators in science like Dr. Swain. He’s been an invaluable source of information for me since I moved to the Central Coast from DC a few years ago.

  3. I remember, what must have been after the 1997/98 winter, PV School holding their Annual Carnival on Memorial Day weekend. A slide btw north Willow (actually Broken Truck) & the eucalyptus grove, went across both lanes after months of no rain. Luckily there was a turnout that one could drive on to bypass it and the Carnival was held. Lesson: anything can happen @ anytime!

  4. I watched the USGS video–fascinating! He lost me at about halfway in (sooo techie) but I reviewed the end. Excellent info. Thank you for the link.

  5. As always, thanks for keeping us up to date on the perils of mudslides & CA-1!

    Cambria Library is open again, Yay!. Though the small mudslide on the steep slope above it is still moving. And in fact coming over the retaining wall above the parking lot!

  6. Thanks Kate! Very valuable information for us. I look forward to checking out the links.

  7. Super interesting, Kate. Thank you for all of your research and posting. Being ‘another weather nerd’ I’m now a follower of Dr. Swain. 🙂

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