Landslide on California highway part of $1 billion in damage 

Posted: May 24, 2017 by oldbrew in Geology, News, weather

California’s Big Sur coast – ‘considered one of the finest images’ by Wikipedia


The end of the California drought hasn’t been all good news for everyone, due partly to what may be ‘the largest mudslide in the state’s history’.

A massive landslide that went into the Pacific Ocean is the latest natural disaster to hit a California community that relies heavily on an iconic coastal highway and tourism to survive, and it adds to a record $1 billion in highway damage from one of the state’s wettest winters in decades, reports SFGate.

The weekend slide in Big Sur buried a portion of Highway 1 under a 40-foot layer of rock and dirt and changed the coastline below to include what now looks like a rounded skirt hem, Susana Cruz, a spokeswoman with the California Department of Transportation, said Tuesday.

More than 1 million tons of rock and dirt tumbled down a saturated slope in an area called Mud Creek. The slide is covering up about a one-quarter-of-a-mile (0.40-kilometer) stretch of Highway 1, and authorities have no estimate on when it might re-open. The area remains unstable.

“We haven’t been able to go up there and assess. It’s still moving,” Cruz said. “We have geologists and engineers who are going to check it out this week to see how do we pick up the pieces.”


It’s the largest mudslide she knows of in the state’s history, she said. “It’s one of a kind,” Cruz said.

One of California’s rainiest and snowiest winters on record has broken a five-year drought, but also caused flooding and landslides in much of the state and sped up coastal erosion.

“This type of thing may become more frequent, but Big Sur has its own unique geology,” said Dan Carl, a district director for the California Coastal Commission whose area includes Big Sur. “A lot of Big Sur is moving; you just don’t see it.”

Even before the weekend slide, storms across California have caused just over $1 billion in highway damage to more than 400 sites during the fiscal year that ends in June, Mark Dinger, also a spokesman for the state transportation agency, said Tuesday. That compares with $660 million last year, he said.

Big Sur is one of the state’s biggest tourist draws in a normal year, attracting visitors to serene groves of redwoods, beaches and the dramatic ocean scenery along narrow, winding Highway 1.

Continued here.

Comments
  1. wildeco2014 says:

    I’m currently in Carmel and had been hoping to drive Big Sur but clearly now cannot.
    It is all the fault of the reversal of the past warming trend with jet stream tracks now having moved further towards the equator once more so as to more affect the Big Sur region.

  2. oldbrew says:

    Bad luck SW. Parts of the coast road were already restricted due to earlier, smaller landslips and risks thereof.

    ‘Locals say the new avalanche of mud rivals a notorious slide in 1983 that covered Highway 1 to the north at Julia Pfeiffer Burns State Park. That blast of debris took 14 months to clear.’

    http://www.sfgate.com/bayarea/article/Big-Sur-hit-again-as-huge-landslide-covers-11167872.php

    At the aptly-named Mud Creek ‘more than a million tons of debris buried the road and crashed into the sea, officials said.’

  3. Martin Miller says:

    Landslides along this section of highway 1 (or as locals like me [So Cal resident for over fifty years] call it PCH) are commonplace. When it rains there is going to be a slide somewhere along the road. Everybody knows it, CalTrans had a report written to the effect back in 2001, http://www.dot.ca.gov/dist05/projects/bigsur/inventory_reports/landslide_report_final.pdf. This area has been prone slides and building the road has merely added more instability. Still, it is an amazing place to visit if you get the chance.

  4. oldbrew says:

    Maybe a few (more?) of these will be needed, as seen in the European Alps.

  5. RACookPE1978 says:

    We discussed this slide last night at http://www.freerepublic.com
    From comment nbr 38 of that thread

    http://www.freerepublic.com/focus/news/3554694/posts?page=38,

    this link

    http://www.californiacoastline.org/

    has a series of California Coastal Road photographs from south to north.

    Photograph nbr 200806523 and 200806524 in the California Coastal Road survey shows this part of the road BEFORE the slope collapsed.

    [reply] thanks RA

  6. oldbrew says:

    From SFGate’s helicopter video:

    You have to wonder if a road like that would ever be open to private vehicles (tourists) in the UK for example. Obviously residents accept the risk.

  7. E.M.Smith says:

    @Oldbrew:

    That road is the only way to get to coastal communities for a few hundred miles of coastline. I’ve driven it from end to end. One of the most glorious, if slow, drives in the USA.

    In quakes, that dirt and rock gets thrust upward (sometimes feet at a time ) but that makes it too steep to be stable. Land and mud slides let it slump back to a stable angle. Rinse and repeat on millenial time scales.

    The only alternative would be to abandon the coast range area, or about 1/4 of the State, and the best bits at that.

    Are the Kiwis ready to abandon North Island due to the Supervolcano? South Island from the quakes? Are Japanese abandoning coastlines due to tsunami risks? Italians leaving Vesuvius?

    Folks generally know not to be there on stormy nights when most slides seem to happen, and to watch carefully in the following days. Hwy 17 between Silicon Valley and Santa Cruise beach boardwalk (with surfing and fishing) gets blocked by slides a couple of times a year. It is also jam packed most days. Commuters weekdays, beach party weekends. Only rarely is there a body count, and then usually a small one. Less than the traffic accidents on clear days. Why? Small stuff starts to fall before the slide. Folks see it and clear the section. Usually works.

    BTW, the shed covers don’t do much for this area. It is the entire topsoil layer that tends to decouple from the bedrock under hydraulic pressure. Hard to anchor things such that a moving mountain doesn’t move them.

    At Devil’s Slide area, they just got tired of the annual closures and moved the whole road inland a ways, bypassing that mountain on the backside. They were lucky and had flat there. Most of hwy 1 just has ever higher mountain and more slide issues inland.

    Want a coast view? Then you accept it. Don’t accept it? Leave and order a photo album…

  8. oldbrew says:

    EM Smith says: ‘Folks generally know’

    Yes but that’s my point – tourists generally don’t.

  9. Timo Soren says:

    Not unprecedented as they LOVE to say. Even the La Concita (sp) mudslide was on the order or 1.5 million cubic meters. This is in that ballpark, as a physicist would say ‘on the order of magnitude of’.

  10. John Andrews says:

    We did that road on our honeymoon in 1961. I will never forget it.

  11. oldbrew says:

    Meanwhile, The LA Times reports…

    The reopening of Tioga Pass, the key east entrance to Yosemite, is a sign of the coming summer as sure as baseball returning to Chavez Ravine, or the swallows returning to Capistrano. Typically it occurs in time for the Memorial Day [last Monday in May] rush.

    This year, the still-snowed-under Tioga Pass may not open till almost July 4.

    Crews continue to carve away at mountains of snow three stories high, the bulldozers working from top to bottom, one layer at a time, till the snow is thin enough to allow rotary plows to move in and scrape away the rest.

    Current snowpack in parts of the central eastern Sierra is 220% of average for this date. [bold added]

    http://www.latimes.com/travel/deals/la-tr-tioga-pass-20170522-story.html
    – – –
    Remember things like this when reading stories that say ‘as the world warms’.

  12. Bulaman says:

    @Oldbrew:
    Photo is of the Otira gorge between Greymouth and Christchurch, New Zealand, not Europe!.
    Drove through there on Wednesday in sunny and cold weather.

  13. oldbrew says:

    Bulaman – here’s the caption from the SFGate report…

    ‘This aerial photo taken Monday, May 22, 2017, and provided by John Madonna, shows a massive landslide along California’s coastal Highway 1 that has buried the road under a 40-foot layer of rock and dirt. A swath of the hillside gave way in an area called Mud Creek on Saturday, May 20, covering about one-third of a mile, half a kilometer, of road and changing the Big Sur coastline.’
    http://www.sfgate.com/bayarea/article/Big-Sur-hit-again-as-huge-landslide-covers-11167872.php

    Just went on Google maps for Mud Creek, CA and they showed the same photo. Here’s Google’s satellite view (pre-landslide). The wiggly road at lower right is also on the pic I showed earlier.

  14. E.M.Smith says:

    @Oldbrew:

    You edited out a key part of that sentence “stormy nights”. Tourists, that you worry so much about, generally avoid California in the stormy season, and when here during storms anyway, are not found out driving on dark stormy roads, but at the bar or in bed.

    There is a very steep cliff on one side, and sharp frequent turns in many parts, on a very narrow road (some wider than others). Driving in dry sun takes attention. Driving at night in a storm is, er, “challenging”, and anyone doing it is most at risk from leaving the road or hitting other cars.

    Simply put, you have misplaced worry. The slides are mostly an annoyance. The cliff and traffic are the risks.

    Oh, and for truly clueless tourists, the State puts up road signs saying “Rock Slide Area” in those parts most prone to slides and slumps. There is ample warning to anyone who can pass a drivers license eye test…

    There are traffic fatalities daily on those same slide prone roads from folks hitting each other or going over the edge. I can’t remember the last fatality due to slide vs vehicle. (I do remember several fatalities from slide vs house with folks sleeping… so not a failure of remembering) worry about the oncoming car with a driver staring at the sunset or the mountain views, they are the danger, not the midnight slide where the odds of any one person being hit are many millions to one. Even for tourists.

    Oh, and if you are a tourist here and it has rained for several days straight, spend the evening in the bar, not driving near the cliffs… in the morning, the road crews will inspect the risk areas and close them if slumping has started. There is a video in this story showing how a slide starts with a few rocks, then picks up speed.

    http://www.wlky.com/article/workers-run-from-massive-rock-slide-1493309011/9570825

    The workers were able to run away from the slide area on foot. When some car is hit by one of these events, it is usually a rock in the starting phase, not the slide proper. The first few rocks are the warning of a possible slide event, folks see them and clear the area if in it, or stop before entering the rocks in front of them. Scary? Sure. But much slower and avoidable than a 70 mph headon from some damn fool leaving their lane.

    Basically, if there are sporadic rocks rolling into the road, stop befor entering or drive out if already in it. Most folks seem to “get that” without special training… not liking being hit by rocks and all. Some few times, the first couple of rocks hit a car, mostly causing minor vehicle damage. I’ve put about a million miles on driving here (250,000 in 2 years on one job “on the road”). I’ve seen rocks entering the road twice, and some sitting static on the shoulder a few more (so they fell, but no slide). Never seen a slide happen. I’ve never seen vehicle damage, only rare news reports. So it happens, but is a news event. In that million miles and half century, I rate “rock slide risk” as irrelevant and miniscule.

    Wet roads and cliffs are a far higher risk. (I’ve seen several cars off road. Three times I came close, narrow escapes…) Drunk drivers and red light runners orders of magnitude higher than that. Flat tires are a greater risk I’ve had two blowouts at inconveient times almost toss me off a cliff… (a lot happens in a million miles… and I think I’m actually over that. I’ve put 250,000+ on four of my cars and more on others like the spouse’s )

    I worry more about wet roads and checking tire pressure than rock slides. The first two have demonstrated they are a big risk. Several times.

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