debris flow event | 25 December 2003 | Devore, California

[SittingMooseShaman]

...well, there lay all the material needed for that backyard water feature ya always wanted...delivered free!

[hebneh]

For water that isn't very deep, those huge rocks are certainly traveling fast. Hard to believe, in fact, that such big boulders are being tumbled down this street at all.

[Alexknobsob]

Great video

[Snauzer67]

I hate landslides and the likes.

[mitch8769]

the comments made on youtube are sometimes the most amusing part of surfing the vidz.

[todotodo101]

haha. too true.

[football9999999]

thats weird my last name is devore

[bapyou]

You think that your last name is weird?

[football9999999]

no it is weird that my last name is the same name as the town

[bapyou]

Why is it weird that your last name is the same name as the town?

[football9999999]

its not that hard to understand. there is a town on the other side of the country that has the same name as me. Think a little bit

[bapyou]

Well, I don't have a clue as to where you come from. How could I? As for the name of the town, towns are often named after a founder. Probably there was some guy named Devore for whom the place was named. Devore is an unincorporated part of San Bernardino County, Calif. It's a nice area. But, as this video attests, Devore has it's share of hazards with which it has to deal from time to time. In addition to debris flows, Devore is located directly on top of one section of the San Andreas fault.

[football9999999]

oh. yeah i lie in maryland sso thats why i thought it was weird;. i will have to do some research on the town

[bapyou]

FYI - There's not much on the internet about Devore, CA. I've looked. Let me know what you find out. If anything.

[raymondlawust]

The flow event is really a strong one. Where did those boulders from? They look very deadly.

[bapyou]

Debris flows occur when high intensity rains fall on relatively steep watersheds with abundant loose materials in the upper parts of the watershed. As to your question "Where did those boulders from?", the answer is: They were weathered loose (worn away) from the bedrock in the upper parts of the watershed. This event occurred on the slopes of the San Bernardino Mts where lots of bedrock and loose earth materials are present in the upper parts of the watersheds. Hike around and you'll see them.

[raymondlawust]

As the watershed has such a good supply of boulders, it seems that some mitigation measures such as boulder fences (or sometimes rock nails) are necessary....

[bapyou]

Raymond: The info above that I wrote as a reply to your last post was very general. I don't know the specifics of this local watershed. Could be that this event "cleaned out" (so to speak) the "supply of boulders" that was hanging around the upper parts of the watershed for a good long time to come. Some places in So Cal (mostly along the San Gabriel Mtn front) have debris basins which trap flows such as this one. They also have fences, which fill up quickly & are expensive to clean out.

[lelesan85]

in my opinion is a mud/debris flow...debris flow have less water and more ruditic components...but I can wrong...

[bapyou]

I agree with you. It's a very watery mix.

[whoseurgranny]

thats a pretty violent slide.

[bapyou]

Hello. It's not a landslide per se. It's really a debris flow. A landslide doesn't have this much water. Debris flows are mobilized masses of water and mud and rocks that form in steep canyons when there is a high intensity rainfall event. They travel dwon-canyon and fow like you see here in this vid.

[bapyou]

Sorry, that last sentence should have read:

"They travel down-canyon and flow like you see here in this vid."

[ZombiedustXXX]

Yup, the asphalt pavement below the modern 15 is the old Route 66. The first exit North above the merge 15/215 is called Kenwood. I never have ventured that way off-pavement. On Fridays, there are always fellas in civilian pickup trucks on the sides of the road, adjacent to the tracks. They do not seem to be doing much. I gather these are just railroad workers keeping an eye on people ready to "find a shortcut"...and endanger their lives by impeding into railroad property.

[bapyou]

OK Zombie, I can tell that you are very familiar with that area. You are 100% correct. That old asphalt road was Route 66 way back when. I didn't remember the name of the exit and you knew it! I can't speak for the "fellas in civilian pickup trucks...adjacent to the tracks". I was there last December and saw no one. It was a Sunday. The railroad crossing has barriers I believe.

[bapyou]

2. There is a church up in Lone Pine Canyon that is only accessible by using this road. The parishoners attend services at the church on Sundays. Me and my friends had no problem driving through there back in December. None at all.

Someone, recently, wrote a car trip-oriented guide book to the San Andreas fault. Don't recall the author's name offhand. He was interviewed on the radio.

[ZombiedustXXX]

Yup, at the first large sweeping right-hand turn of the Cajon Pass after the the 15 and 215 merge(on the driver's side of a car going North), is a canyon that rises from the floor to the West. I know exactly where you are talking about.

[bapyou]

Zombie: Good to see that you are informed. Most people haven't a clue as to the whereabouts of the SAF. BTW, that canyon is called Lone Pine Canyon. If you have a rough vehicle (one you don't mind getting dirty or driving on gravel) you can get off the first exit going north on the 15 after Devore; after a few miles look for a road that goes off and down to the left. The road crosses Cajon Creek and also a set of railroad tracks. Then it starts to climb up through Lone Pine Canyon. cont...

[bapyou]

....Eventually the gravel/dirt road meets a paved road that will take you up to Wrightwood. As you drive up LPC, take note of the very different rock types on the south and north sides of LPC. This is due to the offset of the SAF.

[ZombiedustXXX]

It's a fantastic/beautiful drive, compared to what most people in SoCal experience. All this stuff interests me, although I never had the chance to study this typre of thing in earnest.

[ZombiedustXXX]

This is some stunning video, I drive up/down the Cajon Pass everyday. I had no idea it was this bad that year!

Most people would only know Devore as the only place to buy beer/chips/soda for the annual Ozzfest in So Cal in the summer heat.

I remember this storm because the "shortcut" bypassing the normal Northbound 15 Highway through Devore was washed out the very road that is the entrance to Hyundai Pavillion.

[ZombiedustXXX]

sorry for the typos!

[bapyou]

Hey <u>Zombie</u>. Thank you for the comment. Don't worry about your typos. This here is Internet First Draft Theater. We're all misspellers at some point in time.

Whenever there is a fire in the mountains of SoCal and the burned area receives a high magnitude storm during the following rainy season, there is the possibility of debris flows occurring like the one depicted in this video. Debris flows are a part of the southern California environment.

[bapyou]

Also, if you didn't know already, north of Devore, in the Cajon Pass, you are driving directly along and in the San Andreas fault for several miles. In fact, the SAF is the reason Cajon Pass is located where it is. Cheers!

[batholith5]

that looks like a crazy fun thing to slide down in a boat or something :P

[bapyou]

Hey! Why don't you try it sometime? Just wait for a big storm. Just watch out for those car-sized boulders.

[vanawesome]

YIKES!! That's crazy sauce right there! I remember those fires. You live in california?

[bapyou]

It's right on my YT page: Yes. I live in L.A. We're practically neighbors. I did not shoot this vid, though. It was sent to me by a woman who researches landslides at the U.S. Geological Survey in Colorado who got it from a guy in Devore, CA. The vid was shot Xmas day 2003. Detailed info is in the vid description, if you want it. I remember the ash floating in from the fires out to the east of L.A. in October 2003. Deeply spooky time. Those fires preceded this debris flow.

[vanawesome]

woops, sorry for not looking at your channel for the info. I just moved out of LA. Couldn't take all the traffic all the time. Love it up here in Thousand Oaks. Yah, that's one of the craziest things i've ever seen.

[99tollap]

...in a physical setting (posted before I finished!).

[bapyou]

Hey, fantastic! Just a bit more info:

The location of this debris flow event is relatvly rural. Around the margins of the L.A. (where I live), large concrete bowl-shaped structures were built decades ago to collect the debris flow material that comes down out of the mountains during a good rain year. Afterwards they are cleaned out & the material hauled away. The essay "Los Angeles Against the Mountains" in John McPhee's <i>The Control of Nature</i> (FSG 1989) details this situation.

[bapyou]

One other thing:

This particular event is a relatively watery debris flow. Some other debris flows will have a greater ratio of fine material by which the larger clasts are supported.

Tell your prof about this video & good luck with your examination!

[99tollap]

Geology at Bristol University, UK. Im currently revising for an exam on hazardous flows/flow dynamics. It's great to see the theory

[99tollap]

Just studying these things at university. Thanks for the great video.

[bapyou]

Hey! Thank you for the comment. Where do you study?