Friday, April 14, 2017

Roads and Landslides and Mud - Oh My!

Well, the original plan called for us driving up Highway 1 along the coast from California all the way to Washington. This is a classic trip that many, like us, dream of making.  Not so fast.  This winter's big storms and flooding that you might have seen them on the news have caused the Pfeiffer Canyon Bridge to fail (one of the bridge pilings was built on a mud slide). Now Hwy 1 is closed, by some estimates until September 30th. This is a big deal because Hwy 1 is the main, and in most places only paved road along the coast.  Here is a news report with some cool video of the bridge demolition.  It turned out that the road was actually closed in four different locations, and many businesses and homes are cut off from the world.

When we lived on the Oregon coast, many years ago, we got somewhat used to the recurring mudslides after each major rain storm. Somehow the soils seem only tenuously attached to the rock, which themselves seem to have only a loose grip on the mountains below.  The rain creates a slippery, greasy layer of slickums, and the top surface breaks loose, sliding down the mountain  It's really common to see that a landslide occurred when you watch the news on the west coast.

This past week of our trip, road problems became a bit of a theme: The road into Sequoia National Park: closed due to a snow storm.  The scenic road through the Redwood National Park: closed due to a fallen tree that took out a big chunk of hillside and a chunk of the road. The road west across the mountains: Partial closures due to an enormous mudslide. Route 1 along the coast, closed in four places: Again and again, one lane traffic, traffic lights in middle of the woods, slow traffic, flaggers, rock slide, mud slide, jersey barriers.  More time to admire the scenery ;)

At the end of this blog, there are some pictures of attempts to stabilize the earth, but this is what we saw:

Here you can see how a slide starts
A smallish road cut giving way, have a look at the telephone poles HWY 1
I guess they really mean it
A fresh rock fall, not a good thing for your tires to drive over, or to take on your windshield
Here you can see how Hwy 1 is clinging to the headlands  If you can't figure the picture out, Hwy 1 is the horizontal line about 1/4 of the way down the picture.  The rest is cliff, and at the bottom is a bit of the ocean waves crashing.

Picture yourself as a five year old making a too wet mud cake, and you get the idea.  You can see how that whole u-shaped bit sloughed off.
This is the mother of all slides. It closed the main route to the coast (Redding to Arcata) for months, if you look closely you can see the one lane dirt road that has been reopened.   That's a VERY big excavator working alongside the Trinity River
Somewhat exciting when you are towing a trailer....
Not much of a road to begin with, but this 140 mile road is still the best way to get to the coast.

These are actually quite big rocks falling.

Here, an array of chip-filled waddles are supposed to hold the bank up.  They're staked in, and then it was seeded with grass.  I believe there's some geotextile fabric under the waddles.
You could see they were experimenting in different places to try to devise new techniques to hold back the earth.

These pipes are designed to drain the water from the earth to reduce the weight and lubrication which leads to the slides.  The horizontal pipes are typically perforated pipes, which can collect water along their length, and then the black hoses lead down to a concrete culvert that safely takes the water away.  The rock is called riprap, and is deployed to prevent surface erosion of the soil.

Seems to just be a giant tarp in place temporarily to prevent erosion during an intensely rainy weekend.  I guess they'll do something permanent soon.

Here, the road just fell off the mountain, and that purple rebar is where they will pour a new concrete road.  I don't know what will keep it from falling off the mountain.

There's a lot of wicked tight corners on HWY 1, and a lot of fast drivers, since its the only road to get anywhere on the coast.  To the right, you can see a wooden retaining wall designed to hold back the road cut.

As I said earlier, the scenery makes the driving worth it.  As my nephew would say, "Oh Yeeah...."

1 comment:

  1. Sounds like you've really earned your "Road Warrior" stripes this week. The "roads vs landslides" reminds me of the "ocean front homes vs hurricanes" on the Atlantic coast. Be safe!